Abstract:
A method for manufacturing an insert-resin-molded product prevents resin burrs from being generated. The method includes the steps of: preparing a resin-molding mold having a cavity having an inner wall including a recess formed therein; preparing a metallic member to be placed in the cavity of the resin-molding mold so as to be integrally molded with resin, the member having a metallic part to be fit into a recess of the resin-molding mold; placing the metallic member in the cavity of the resin-molding mold and fitting the metallic part of the metallic member into the recess of the resin-molding mold; and injecting resin into the cavity of the resin-molding mold to integrally insert-resin-mold with the metallic member.

Description:
This application corresponds to Japanese Patent Application No. 9-255302, filed on Sep. 19, 1997, which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method for manufacturing an insert-resin-molded product which is molded by means of integrating resin with a metallic member, and a product produced thereby. 
     2. Description of the Related Art 
     A description will be given of a conventional method for manufacturing an insert-resin-molded product, with reference to FIGS. 4 through 6. The described figures and method are not “prior art,” but “related art.” 
     As shown in FIG. 4, a chip-type connector  1  is formed as an insert-resin-molded product. The connector comprises an outer conductor  2  as a first metallic member, an inner conductor  3  as a second metallic member, and resin  4  which is molded by means of integrating resin with the metallic members. 
     First, the outer conductor  2  and the inner conductor  3  are prepared. The former, as shown in FIG. 5, is formed by a substantially pipe-shaped cylindrical portion  6  at the center thereof, a flange-like top surface portion  7  formed at one end of the substantially pipe-shaped cylindrical portion  6 , metallic parts  8   a  and  8   b  which are formed by bending the end portions of the top surface portion  7  in the direction of the substantially pipe-shaped cylindrical portion  6 , and legs  9   a  and  9   b  connected to the ends of the metallic parts  8   a  and  8 b. The metallic parts  8   a  and  8   b  have through-holes  10   a  and  10   b  disposed at approximately the respective centers thereof. The metallic parts  8   a  and  8   b  have shapes that substantially resemble the letter “U.” The through-holes  10   a  and  10   b  are made by cutting out two respective portions on the top surface portion  7 . A detailed description will be omitted of the inner conductor  3  shown in FIG. 4, as such a detailed description is unnecessary for the purpose of this disclosure. 
     Next, as shown in FIG. 6, there is prepared a resin-molding mold  32 , which has a cavity  31  capable of accommodating the outer conductor  2  and the inner conductor  3 . The cavity  31  is formed into a rectangular parallelepiped, at the center of which a protrusion  34  is disposed so as to be fitted into the inner periphery of the cylindrical portion  6  of the outer conductor  2 . Inner walls  33  of the cavity  31  are flat, except for the region of the protrusion  34 . The resin-molding mold  32  shown in FIG. 6 forms a lower mold portion. An associated upper mold portion, which is not shown in FIG. 6, is equipped with a gate for injecting resin. The upper mold portion lays flat across and encloses the upper opening  35  of the cavity  31 . 
     Inside the cavity  31  of the resin-molding mold  32 , the outer conductor  2  and the inner conductor  3  are accommodated in a state in which these components remain insulated from each other. Molten resin  4  is injected into the cavity  31  of the resin-molding mold  32  after the upper opening  35  of the cavity  31  is enclosed by the upper mold portion. After the resin  4  injected into the cavity  31  has set, the whole device is taken out from the resin-molding mold  32 . A chip-type connector  1  is thereby obtained. More specifically, the device obtained is an insert-resin-molded product integrating the outer conductor  2 , the inner conductor  3  and the resin  4  into a unit, as shown in FIG.  4 . 
     As for surfaces of the chip-type connector  1 , referring to FIG. 4, a description will be provided using a side surface A of the device as an example. The end portions S 1  and S 3  and the center portion S 2  of the resin side surface, which are connected to the metallic part  8   a , are formed flush with the surface of the metallic part  8   a  of the outer conductor  2 . The side surface A of the chip-type connector  1  is made flat in conformity with the configuration of the flat inner wall  33  of the cavity  31 , which corresponds to the side surface A, as shown in FIG.  6 . 
     In the above method for manufacturing the chip type connector  1 , however, when the mold is filled to excess with the molten resin  4 , the resin  4  may flow over the surface of the metallic part  8   a , which is flush with the resin surfaces S 1 , S 2  and S 3 . As a result, the resin may be deposited on the surface of the metallic part  8   a , resulting in the formation of “resin burrs”  5 . 
     Additionally, when a configuration of the corner portion R 1  of the bent metallic part  8   a  (shown in FIG. 5) differs from a configuration of the corresponding corner portion R 2  of the cavity  31  (shown in FIG.  6 ), the resin  4  may flow over the surface of the corner portion of the metallic part  8   a  in a manner similar to that described above. Consequently, resin is deposited on the surface of the metallic part  8   a , so that resin burrs  5  (Shown in FIG. 4) are generated. 
     SUMMARY OF THE INVENTION 
     The present invention has been made with a view toward solving at least the above-noted problems. Accordingly, it is an object of the present invention to provide a method for manufacturing an insert-resin-molded product, in which the generation of resin burrs on the surface of a metallic member caused by insert-resin-molding is prevented. 
     To this end, in accordance with the present invention, there is provided a method for manufacturing an insert-resin-molded product comprising the steps of: preparing a resin-molding mold having a cavity with an inner wall having a recess therein; preparing a metallic member to be placed in the cavity and to be integrally molded with resin, the metallic member having a metallic part which fits into the recess of the resin-molding mold; placing the metallic member in the cavity of the resin-molding mold and fitting the metallic part of the metallic member into the recess of the resin-molding mold; and, in this state, injecting resin into the cavity of the resin-molding mold to insert-resin-mold integrally with the metallic member. 
     Preferably, the recess of the resin-molding mold is formed in such a manner that the side surface of the recess is substantially perpendicular to the bottom surface of the same. This allows the flow of the molten resin to be substantially perpendicular to the side surface of the metallic member, so that the resin does not flow in the direction of the side surface of the metallic member, thereby, preventing resin burrs from being generated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing, and other, objects, features and advantages of the present invention will be more readily understood upon reading the following detailed description in conjunction with the drawings in which: 
     FIG. 1 is a perspective view of an exemplary insert-resin-molded product manufactured by a method according to an exemplary embodiment of the present invention; 
     FIG.  2 ( a ) is a perspective view of a lower mold portion of a resin-molding mold employed in the method for manufacturing the insert-resin-molded product according to the above-mentioned embodiment of the present invention; 
     FIG.  2 ( b ) is a cross-section of the device shown in FIG.  2 ( a ) along line A—A, including an outer conductor accommodated in the resin-molding mold; 
     FIG. 3 is a perspective view illustrating a state in which an outer conductor is accommodated in the resin-molding mold shown in FIG. 2; 
     FIG. 4 is a perspective view of an insert-resin-molded product formed according to a conventional manufacturing method; 
     FIG. 5 is a perspective bottom view of the outer conductor used in the insert-resin-molded product shown in FIG.  1  and FIG. 4; and 
     FIG. 6 is a perspective view of a lower mold portion of a resin-molding mold used in the conventional method for manufacturing an insert-resin-molded product. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 through 3, a detailed description will be given of an exemplary embodiment of the present invention. The parts which are the same or similar to the parts previously discussed are denoted by the same numerals, and a detailed description thereof will be omitted. 
     As shown in FIG. 1, there is provided a chip-type connector  21  formed as an insert-resin-molded product, which comprises an outer conductor  2  as a first metallic member, an inner conductor  3  as a second metallic member and resin  22  molded integrally with the above-identified metallic members. 
     First, the outer conductor  2  and the inner conductor  3 , which are metallic members, are prepared. 
     Next, as shown in FIG. 2 (which includes FIGS.  2 ( a ) and  2 ( b )), a resin-molding mold  12 , which has a cavity  11  capable of accommodating the conductors  2  and  3  therein, is prepared. Through-holes  10   a  and  10   b  of the outer conductor  2  are formed to define substantially U-shaped metallic parts  8   a  and  8   b . Substantially U-shaped recesses  13  and  14  are disposed on opposing inner walls of the cavity  11 . The metallic parts  8   a  and  8   b  are respectively fit into the recesses  13  and  14 . The vertical side surfaces  13   a  and  14   a  of the recesses  13  and  14  are formed almost perpendicularly to bottom surfaces  13   b  and  14   b  of the recesses  13  and  14 , and more generally, all of the adjoining surfaces which form the recesses  13  and  14  can be disposed perpendicularly to each other. A protrusion  17  is disposed at the center of the cavity  11 , into which an inner periphery of a substantially pipe-shaped cylindrical portion  6  is fit. A resin-molding mold  12  shown in FIG. 2 forms a lower mold portion. There is also an upper mold portion, which is not shown here, with a gate for injecting resin. The upper mold portion is placed flat across and encloses the top opening of the cavity  11 . 
     As shown in FIG. 3, the outer conductor  2 , and the inner conductor  3  (not shown) are accommodated in the cavity  11  of the resin-molding mold  12  in a state in which they remain insulated from each other. A molten resin  22  is injected into the cavity  11  of the resin-molding mold  12  after the top opening  18  of the cavity  11  is enclosed by placing the upper mold portion flat across the top opening  18 . 
     Then, the whole device is removed from the resin-molding mold  12  after the resin  22  which has been injected into the cavity  11  has set. A chip-type connector  21  shown in FIG. 1 is thereby obtained, which comprises an insert-resin-molded product made by means of integrating the outer conductor  2 , the inner conductor  3 , and the resin  22  into a unit. 
     Referring to FIG. 1, a description will be given of the surfaces of the chip-type connector  21 , focusing on the side surface of the FIG. 1 embodiment which corresponds to the previously discussed side surface of the conventional example shown in FIG.  6 . 
     The surface of the metallic part  8   a  of the outer conductor  2 , and S 4 , S 5  and S 6  which are resin surface portions connected to the metallic part  8   a , are not flush with each other. Namely, the metallic part  8   a  fitted into the recess  13  which is disposed in the cavity  11  of the resin-molding mold  12  protrudes out, and steps are formed in such a manner that the resin surface portions S 4 , S 5  and S 6  connected to the metallic part  8   a  are recessed with respect to the metallic part  8   a  . 
     When an insert-resin-molded product is manufactured, the filling of the cavity  11  with an excessive amount of resin  22  causes the resin  22  to be connected to an end surface  8   a  l of the metallic part  8   a  . Then, resin  22   a  flush with the end surface  8   a  l flows in the direction of the end surface  8   a  l. That is, the resin  22   a  flows in the direction of a side surface  13   a  of the recess  13  of the cavity  11 . 
     Further filling of the cavity with an excessive amount of resin allows the resin  22   a  to flow in a direction along the surface of the metallic part  8   a  . Thus, this causes the resin  22   a  to flow in the direction of a bottom surface  13   b  of the recess  13  from the side surface  13   a  of the recess  13  of the cavity  11 . 
     One exemplary flow pattern of the resin may be understood with reference to FIG.  2 ( b ), which shows a sectional view taken along the line A—A of FIG.  2 ( a ), with the outer conductor  2  fit into the recesses  13  and  14  of the cavity  11 . As indicated there, since the side surface  13   a  of the recess  13  is substantially perpendicular to the bottom surface  13   b  of the recess  13 , the resin  22   a  changes its direction of flow in the direction of 90° to the direction of the bottom surface  13   b  from the direction of the side surface  13   a . That is, the resin flows in the direction of the arrow “R,” but does not readily flow in the direction of arrow “S.” This is partly due to the fact that the metallic parts  8   a  are snugly accommodated in the recesses  13  and  14 , and that the outer surfaces of the metallic parts  8   a  are separated and essentially “sealed off” from the normal flow of resin, making it unlikely that the resin can flow over the surfaces of the metallic parts  8   a  . As a result, resin burrs are not generated. 
     Also, even if a configuration R 1  (shown in FIG. 1) of the corner portion of the bent metallic part  8   a  is not equivalent to a configuration R 2  (shown in FIG. 2) of the corner portion of a cavity  11 , resin  22  does not flow over the surface of the corner portion of the metallic part  8   a  . As a result, no resin burrs are generated, unlike the case the described above. 
     The method for manufacturing an insert-resin-molded product according to the present invention is not restricted to the embodiment above and can be modified in various ways without departing from the spirit and the scope of the invention. For instance, in the above embodiment, the recesses  13  and  14  are arranged respectively on the opposing side surfaces of the cavity as shown in FIG.  2 . This arrangement permits formation of steps on the resin surface portions connected to the metallic parts  8   a  and  8   b  with respect to the metallic parts  8   a  and  8   b  of the outer conductor  2 . However, other options are available. For example, an arrangement of a recess in the bottom surface of the cavity  11  may permit formation of a step (not shown) on the resin surface portion S 7  connected to a top surface portion  7  of the outer conductor  2 . Similarly, an arrangement of a recess on the top surface portion of the cavity  11  may allow a step (not shown) to be formed on a resin surface portion S 8  connected to legs  9   a  and  9   b  of the outer conductor  2 . 
     As shown in FIG. 1, the thickness of the steps between a surface of the metallic part  8   a  and the resin surface portions S 4  and S 6  may be larger than that of the metallic part  8   a  . The thickness of the step between the surface of the metallic part  8   a  and the resin surface portion S 5  may be approximately the same as that of the metallic part  8   a  . However, this should not be construed restrictively. A thinner step portion than the thickness of the metallic part  8   a  can be used. 
     The description of the method for manufacturing an insert-resin-molded product in the embodiment above employs a chip-type connector  21 , but the method is applicable to other various kinds of insert-resin-molded products. 
     As described above, in the method for manufacturing an insert-resin-molded product according to the present invention, a recess in an inner wall of a cavity of a resin-molding mold is arranged and the metallic part of a metallic member is fitted into the recess. This arrangement allows the route of an injected resin to be turned in the middle of the process (e.g., allows the flow of the resin to be changed in the course of the resin-filling process, such as in the manner shown in FIG.  2 ( b )), so that insert-resin-molding with the metallic member in an integrated manner does not permit the resin to reach the surface of the metallic member. Hence, metallic burrs are not generated. 
     Furthermore, metallic burrs are not generated on the surface of the metallic member, since the route of the injected resin turns in a direction substantially at a right angle in the middle of the process for reaching the surface of the metallic part. 
     The above-described exemplary embodiments are intended to be illustrative in all respects, rather than restrictive, of the present invention. Thus the present invention is capable of many variations in detailed implementation that can be derived from the description contained herein by a person skilled in the art. All such variations and modifications are considered to be within the scope and spirit of the present invention as defined by the following claims.