Patent Publication Number: US-2021195758-A1

Title: Resin-sealed in-vehicle electronic control device

Description:
TECHNICAL FIELD 
     The present invention relates to a resin-sealed in-vehicle electronic control device. 
     BACKGROUND ART 
     Concerning an electronic control unit mounted in a passenger compartment of a vehicle, such as an engine control unit or an automatic transmission control unit, there has been a change in installation location such that the electronic control unit is installed in an engine room, on an engine, in a transmission, or the like, and the electronic control unit itself has been downsized. Accordingly, a heat generation rate per unit volume increases, resulting in exposure to higher temperature environments, and demands for vibration resistance and impact resistance increase. 
     To meet such demands, there is disclosed, for example, a technology in which a connector housing connecting a circuit board on which an electronic component is mounted and an external terminal is integrally sealed with a resin (see, for example, PTL 1). According to such a technology, since the circuit board and the like are sealed with the resin, there is an advantageous effect in heat resistance, vibration resistance and impact resistance. 
     CITATION LIST 
     Patent Literature 
     PTL 1: WO 2005/004563 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the related art as described above, a thermal expansion of a resin used for a connector housing is greatly different from that for a sealing resin. As a result, there is concern that the connector housing and the sealing resin may be peeled off at an interface therebetween at the time of cooling after molding and separated from each other according to the progression of the peeling-off. 
     Based on the above-described circumstances, an object of the present invention is to provide a resin-sealed in-vehicle electronic control device having a simple configuration for securely fixing the connector housing and the sealing resin. 
     Solution to Problem 
     In order to solve the above problems, a resin-sealed in-vehicle electronic control device according to a preferred mode of the present invention includes: a circuit board on which an electronic component is mounted; a connector housing that electrically connects the circuit board to an external terminal; and a sealing resin fixing the connector housing to the circuit board. The connector housing has a through hole and/or a cut-out portion allowing communication between a second end surface located opposite to a first end surface on which the external terminal is mounted and a side surface of the connector housing adjoining the second end surface. The sealing resin is continuous to fill at least the inside of the through hole and/or the cut-out portion and cover a part of an outer periphery of the connector housing and at least a part of an outer periphery of the circuit board. 
     In the present specification, the term “external terminal” refers to a terminal of a device other than the resin-sealed in-vehicle electronic control device to be electrically connected to a metal terminal provided in connector housing. In addition, the term “substantially shape” is a concept including, for example, a substantially “T” shape, in which the substantially “L” shape is partially included. 
     Advantageous Effects of Invention 
     According to the present invention, a resin-sealed in-vehicle electronic control device having a simple configuration for securely fixing a connector housing and a sealing resin can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic cross-sectional view illustrating a first embodiment of the present invention. 
         FIG. 2  illustrates modified examples of  FIG. 1 , in which  FIG. 2( a )  illustrates a first modified example and  FIG. 2( b )  illustrates a second modified example. 
         FIG. 3  is an enlarged schematic view illustrating a main portion of  FIG. 1 , in which  FIG. 3( a )  is a projection view of a connector housing and  FIG. 3( b )  illustrates a connected state between the connector housing and a sealing resin. 
         FIG. 4  is a schematic cross-sectional view illustrating an example of a method of forming a resin-sealed in-vehicle electronic control device of  FIG. 1 , in which  FIG. 4( a )  illustrates a state before filling the sealing resin,  FIG. 4( b )  illustrates a state after filling the sealing resin, and  FIG. 4( c )  illustrates a state after mold releasing. 
         FIG. 5  is an enlarged schematic view illustrating a main portion in a second embodiment of the present invention, in which  FIG. 5( a )  is a projection view of a connector housing and  FIG. 5( b )  illustrates a connected state between the connector housing and a sealing resin. 
         FIG. 6  is an enlarged schematic view illustrating a main portion in a third embodiment of the present invention, in which  FIG. 6( a )  is a projection view of a connector housing and  FIG. 6( b )  illustrates a connected state between the connector housing and a sealing resin. 
         FIG. 7  is an enlarged schematic view illustrating a main portion in a modified example of  FIG. 6 , in which  FIG. 7( a )  is a projection view of a connector housing and  FIG. 7( b )  illustrates a connected state between the connector housing and a sealing resin. 
         FIG. 8  is an enlarged schematic view illustrating a main portion in a fourth embodiment of the present invention, in which  FIG. 8( a )  is a projection view of a connector housing and  FIG. 8( b )  illustrates a connected state between the connector housing and a sealing resin. 
         FIG. 9  is a schematic cross-sectional view illustrating a fifth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The resin-sealed in-vehicle electronic control device is a resin-sealed in-vehicle electronic control device including a circuit board on which an electronic component is mounted, a connector housing that electrically connects the circuit board to an external terminal, and a sealing resin fixing the connector housing to the circuit board. The connector housing has a through hole and/or a cut-out portion allowing communication between a second end surface located opposite to a first end surface on which the external terminal is mounted and a side surface of the connector housing adjoining the second end surface. The sealing resin is continuous to fill at least the inside of the through hole and/or the cut-out portion and cover a part of an outer periphery of the connector housing and at least a part of an outer periphery of the circuit board. 
     Hereinafter, first to fifth embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited only to the embodiments described based on the drawings. 
     First Embodiment 
       FIG. 1  is a schematic cross-sectional view illustrating a first embodiment of the present invention. As illustrated in  FIG. 1 , the resin-sealed in-vehicle electronic control device  1  mainly includes a circuit board  11 , a connector housing  21 , and a sealing resin  41 . 
     The circuit board  11  has an electronic component mounted thereon. For example, as illustrated in  FIG. 1 , on the circuit board  11 , electronic components  111  including heat generating electronic components, such as a capacitor and a resistor, are joined to both surfaces of a substrate  110  by soldering or the like, and metal terminals  31  are provided for connection to external terminals that are not illustrated. In addition, as illustrated in  FIGS. 2( a ) and 2( b ) , a metal base  112  for heat dissipation may be mounted on the circuit board  11  via a thermally conductive spacer  113 . As the metal base  112 , a metal base  1121  having heat dissipation fins is illustrated in  FIG. 2( a ) , and a flat metal base  1122  is illustrated in  FIG. 2( b ) . 
     The connector housing  21  electrically connects the circuit board  11  to external terminals. As illustrated in  FIG. 1 , the connector housing  21  has the metal terminals  31  in an opening c thereof, and the above-described circuit board  11  is connected to the metal terminals  31 . As the connector housing  21 , for example, a surface-mount type connector housing (not shown) or the like can be adopted, as well as the connector housing  21  that is in a pin insertion type as illustrated in  FIGS. 2( a ) and 2( b ) . 
     The connector housing  21  of the resin-sealed in-vehicle electronic control device  1  has a through hole  213  in a substantially “L” shape allowing communication between a second end surface located opposite to a first end surface on which the external terminals are mounted and a side surface of the connector housing adjoining the second end surface. As the through hole  213 , for example, as illustrated in  FIG. 3( a ) , it can be specifically adopted that each of a plurality of holes  213   a  and a respective one of a plurality of holes  213   b  communicate with each other, the holes  213   a  extending from each of first to fourth side surfaces  212   a  to  212   d  toward an opposite side surface thereof in parallel with a second end surface  211   b  while being opened in each of the first to fourth side surfaces  212   a  to  212   d , and the holes  213   b  extending from the second end surface  211   b  toward a first end surface  211   a  in parallel with each of the first to fourth side surfaces  212   a  to  212   d  while being opened in the second end surface  211   b.    
     Here, the connector housing  21  and the sealing resin are estimated to have a shrinkage of no greater than about 1 mm. Accordingly, the through hole  213  preferably has a size of 1 mm or more in both width and height (depth). This value is clearly different from a surface roughness size of the connector housing  21 , i.e. several μm to several tens of μm. 
     The through holes  213  in the connector housing  21  are preferably arranged to be symmetrical vertically and horizontally when viewed from above the second end surface  211   b  (see a right side view in  FIG. 3( a ) ). Thus, a stress generated in each through hole  213  can be balanced overall, and the shape can be stably maintained for a long period of time. 
     As a method of forming the through holes  213  in the substantially “L” shape, for example, it can be adopted that when the connector housing  21  is formed by a halved mold or the like, movable pins moving in conjunction with the mold are arranged on the mold in advance to correspond to the respective through holes (e.g. two movable pins/through hole for the through holes in the present embodiment), and the movable pins are pulled out from the respective holes  213   a  and  213   b  of the connector housing  21  immediately before releasing the mold. 
     A material for forming the connector housing  21  is not particularly limited, but the connector housing  21  is preferably formed of a material having flexibility and heat resistance to facilitate production and allow deformation when the external terminals are connected to the connector housing  21 . Examples of preferable materials for forming the connector housing  21  include thermoplastic resins such as polybutylene terephthalate (PBT), nylon 6,6 (PA66), and polyphenylene sulfide (PPS). 
     The sealing resin  41  is a member fixing the connector housing  21  to the circuit board  11 . The sealing resin  41  is continuous to fill at least the inside of the through holes and cover a part of an outer periphery of the connector housing and at least a part of an outer periphery of the circuit board. In the present embodiment, as illustrated in  FIG. 3( b ) , the sealing resin  41  is formed as a single member that is continuous to fill the inside of all of the through holes  213  in the substantially “L” shape and cover a part of the outer periphery of the connector housing  21  and the entire outer periphery of the circuit board (not shown), thereby fixing the connector housing  21  to the circuit board  11 . 
     A material for forming the sealing resin  41  is not particularly limited as long as the effect of the present invention is not impaired thereby, but preferably has heat resistance, high thermal conductivity, vibration resistance and impact resistance to promote heat dissipation from the electronic components  111  and reduce vibration or impact exerted on the circuit board  11  and the connector housing  21 . Examples of preferable materials for forming the sealing resin  41  include thermosetting resins such as an epoxy resin, a phenol resin, an unsaturated polyester resin, a silicone resin, an acrylic resin, and a methacrylic resin. 
     Preferably, the connector housing  21  described above has a larger linear expansion coefficient than the sealing resin  41 . For example, by using an epoxy resin as a material for the sealing resin  41  and polybutylene terephthalate or nylon 66 as a material for the connector housing, the linear expansion coefficient (about 20×10 −6  to 120×10 −6 (1/K)) of the connector housing  21  can be set to be larger than the linear expansion coefficient (about 15×10 −6 (1/K)) of the sealing resin  41 . This makes it easier for the connector housing  21  to shrink than for the sealing resin  41  at the time of cooling the sealing resin  41  when the resin-sealed in-vehicle electronic control device  1  is manufactured, and thus, the connector housing  21  and the sealing resin  41  can further tightly adhere to each other in a firm way. 
     Next, a method of forming the resin-sealed in-vehicle electronic control device  1  will be described. 
       FIG. 4  is a schematic cross-sectional view illustrating an example of a method of forming the resin-sealed in-vehicle electronic control device  1  of  FIG. 1 . For the resin-sealed in-vehicle electronic control device  1 , first of all, the circuit board  11  to which the electronic components  111  are joined by soldering is used, and the metal terminals  31  of the connector housing  21  are connected to the circuit board  11  by soldering. 
     Next, after the circuit board  11  to which the connector housing  21  is joined as described above is set between molds  81  and  82  (see  FIG. 4( a ) ), the molds  81  and  82  are closed and the sealing resin melted in advance is injected into a space between the molds  81  and  82  through a resin injection gate  83  (see  FIG. 4( b ) ). Subsequently, the sealing resin  41  is cured, and then the molds  81  and  82  are opened to take the molded product out (see  FIG. 4( c ) ), thereby obtaining the resin-sealed in-vehicle electronic control device  1  covered with the sealing resin  41 . 
     A thickness of the sealing resin  41  covering the outer periphery of the connector housing  21  is not particularly limited as long as the effect of the present invention is not impaired thereby. For example, the thickness of the sealing resin  41  from a surface of the connector housing can be almost the same as a depth of the through holes. 
     As described above, since the resin-sealed in-vehicle electronic control device  1  has the above-described configuration, it is possible to securely fix the connector housing  21  and the sealing resin  41  to each other based on the simple configuration, without adding a member. As a result, the cost of the resin-sealed in-vehicle electronic control device  1  can be reduced. 
     In addition, in the present embodiment, the sealing resin  41  flowing into the through hole  213  serves as one restraint point, and the metal terminal  31  penetrating through the connector housing  21  and located in the sealing resin  41  serves as another restraint point. Thus, when the resin of the connector housing shrinks between these restraint points, a tensile stress is generated in the connector housing  21  and a shrinkage stress is generated in the sealing resin  41 , and these two stresses are balanced, thereby more firmly connecting the connector housing  21  and the sealing resin  41  to each other. 
     Second Embodiment 
       FIG. 5  is an enlarged schematic view illustrating a main portion in a second embodiment of the present invention. The resin-sealed in-vehicle electronic control device  2  mainly includes a circuit board  11  (not shown), a connector housing  22 , and a sealing resin  42 . The resin-sealed in-vehicle electronic control device  2  is different from that in the first embodiment in configurations of the connector housing  22  and the sealing resin  42 . A configuration of the circuit board  11 , configurations other than shapes of through holes  223  of the connector housing  22  and the sealing resin  42 , and a method of forming the resin-sealed in-vehicle electronic control device  2  are the same as those in the first embodiment. Thus, the same elements are denoted by the same reference signs, and the description of the first embodiment is incorporated by reference therefor. 
     The connector housing  22  electrically connects the circuit board  11  to external terminals. The connector housing  22  of the resin-sealed in-vehicle electronic control device  2  has through holes  223  in a substantially straight-line shape allowing communication between a second end surface and a side surface of the connector housing adjoining the second end surface. As the through hole  223 , for example, it can specifically be adopted, as illustrated in  FIG. 5( a ) , that each of first to fourth side surfaces  222   a  to  222   d  has openings therein and a second end surface  221   b  has a plurality of openings therein, and each of the openings in the first to fourth side surfaces  222   a  to  222   d  communicates with (passes through) a respective one of the openings in the second end surface  221   b  in a straight line. 
     As a method of forming the through holes  223  in the substantially straight-line shape, for example, it can be adopted that when the connector housing  22  is formed by a mold or the like, movable pins are arranged on the mold in advance to correspond to the respective through holes  223  (e.g. one movable pin/through hole for the through holes in the present embodiment), and the movable pins are pulled out from the respective holes of the connector housing  22  immediately before releasing the mold. 
     The sealing resin  42  is a member fixing the connector housing  22  to the circuit board  11 . The sealing resin  42  is continuous to fill at least the inside of the through holes and cover a part of an outer periphery of the connector housing and at least a part of an outer periphery of the circuit board. In the present embodiment, as illustrated in  FIG. 5( b ) , the sealing resin  42  is formed as a single member that is continuous to fill the inside of all of the through holes  223  in the substantially straight-line shape and cover a part of the outer periphery of the connector housing  22  and the entire outer periphery of the circuit board  11  (not shown), thereby fixing the connector housing  22  to the circuit board  11 . 
     As described above, since the resin-sealed in-vehicle electronic control device  2  has the above-described configuration, it is possible to securely fix the connector housing  22  and the sealing resin  42  to each other based on the simple configuration, without adding a member. Furthermore, since the through hole  223  is in the substantially straight-line shape, it is less likely that the flow of the resin spreads towards the movable pins at the time of forming the connector housing  22 . Thus, the connector housing  22  can be expected to be molded more accurately. 
     Third Embodiment 
       FIG. 6  is an enlarged schematic view illustrating a main portion in a third embodiment of the present invention. As illustrated in  FIG. 6 , the resin-sealed in-vehicle electronic control device  3  mainly includes a circuit board (not shown), a connector housing  23 , and a sealing resin  43 . The resin-sealed in-vehicle electronic control device is different from that in the first embodiment in configurations of the connector housing  23  and the sealing resin  43 . A configuration of the circuit board  11 , configurations other than shapes of cut-out portions  233  of the connector housing  23  and the sealing resin  43 , and a method of forming the resin-sealed in-vehicle electronic control device  3  are the same as those in the first embodiment. Thus, the same elements are denoted by the same reference signs, and the description of the first embodiment is incorporated by reference therefor. 
     The connector housing  23  electrically connects the circuit board  11  to external terminals. The connector housing  23  has cut-out portions  233  allowing communication between a second end surface  231   b  located opposite to a first end surface  231   a  on which the external terminals are mounted and a side surface  232  of the connector housing  23  adjoining the second end surface  231   b . As a shape of the cut-out portion  233 , for example, it can specifically be adopted that each cut-out portion  233  is in a rectangular shape to be elongated in such a direction as to become deeper from the side surface  232  to which the cut-out portion  233  belongs, when viewed from above the second end surface  231   b . The direction in which the cut-out portion  233  becomes deeper can be perpendicular to the side surface  232  (see  FIG. 6( a ) ), when viewed from above the second end surface  231   b  (see a right side view in  FIG. 6( a ) ). Alternatively, a direction in which at least one of a plurality of cut-out portions  233   m  belonging to a same side surface  232   m  with respect to a second end surface  231   bm  becomes deeper can be different from that in which another cut-out portion  233   m  of the plurality of cut-out portions  233   m  becomes deeper (see the cut-out portions  233   m  in  FIG. 7( a ) ), when viewed from above the second end surface  231   bm  (see a right side view in  FIG. 7( a ) ). Among them, the cut-out portions  233   m  illustrated in  FIG. 7( a )  are more preferable in that the sealing resin and the connector housing can be more securely fixed to each other. 
     In addition, the cut-out portions  233  in the present embodiment can be formed, for example, by arranging projections (not shown) corresponding to the respective cut-out portions  233  on a mold for forming the connector housing  23 . 
     The sealing resin  43  is a member fixing the connector housing  23  to the circuit board  11 . The sealing resin  43  is continuous to fill at least the inside of the cut-out portions and cover a part of an outer periphery of the connector housing and at least a part of an outer periphery of the circuit board. In the present embodiment, as illustrated in  FIG. 6( b ) , the sealing resin  43  is formed as a single member that is continuous to fill the inside of all of the cut-out portions  233  and cover a part of the outer periphery of the connector housing  23  and the entire outer periphery of the circuit board  11  (not shown), thereby fixing the connector housing  23  to the circuit board  11 . 
     As described above, since the resin-sealed in-vehicle electronic control device  3  has the above-described configuration, it is possible to securely fix the connector housing  23  and the sealing resin  43  to each other based on the simple configuration, without adding a member. 
     Fourth Embodiment 
       FIG. 8  is an enlarged schematic view illustrating a main portion in a fourth embodiment of the present invention. The resin-sealed in-vehicle electronic control device  4  mainly includes a circuit board  11  (not shown), a connector housing  24 , and a sealing resin  44 . The resin-sealed in-vehicle electronic control device  4  is different from that in the first embodiment in configurations of the connector housing  24  and the sealing resin  44 . A configuration of the circuit board  11 , configurations other than shapes of cut-out portions  243  of the connector housing  24  and the sealing resin  44 , and a method of forming the resin-sealed in-vehicle electronic control device  4  are the same as those in the first embodiment. Thus, the same elements are denoted by the same reference signs, and the description of the first embodiment is incorporated by reference therefor. 
     The connector housing  24  electrically connects the circuit board  11  to external terminals. The connector housing  24  has cut-out portions  243  allowing communication between a second end surface  241   b  located opposite to a first end surface  241   a  on which the external terminals are mounted and a side surface  242  of the connector housing  24  adjoining the second end surface  241   b . Concerning a shape of the cut-out portion  243 , each of the cut-out portions  243  is formed to have a shape in which a width of the cut-out portion  243  on a side surface to which the cut-out portion  243  belongs is smaller than a maximum width in the cut-out portion  243 , when viewed from above the second end surface  241   b  (see a right side view in  FIG. 8( a ) ). As the shape of the cut-out portion  243 , for example, it can specifically be adopted, as illustrated in  FIG. 8( a ) , that the cut-out portion  243  has a width that is gradually larger as being farther away from the side surface  242  to which the cut-out portion  243  belongs (a wedge shape), when viewed from above the second end surface  241   b.    
     In addition, the cut-out portions  243  in the present embodiment can be formed, for example, by arranging projections (not shown) corresponding to the respective cut-out portions  243  on a mold for forming the connector housing  24 , injecting a resin into the mold, and then pulling out the mold in a direction perpendicular to the second end surface  241   b.    
     The sealing resin  44  is a member fixing the connector housing  24  to the circuit board  11 . The sealing resin  44  is continuous to fill at least the inside of the cut-out portions  243  and cover a part of an outer periphery of the connector housing  24  and at least a part of an outer periphery of the circuit board  11 . In the present embodiment, as illustrated in  FIG. 8( b ) , the sealing resin  44  is formed as a single member that is continuous to fill the inside of all of the cut-out portions  243  and cover a part of the outer periphery of the connector housing  24  and the entire outer periphery of the circuit board  11  (not shown), thereby fixing the connector housing  24  to the circuit board  11 . 
     As described above, since the resin-sealed in-vehicle electronic control device  4  has the above-described configuration, it is possible to securely fix the connector housing  24  and the sealing resin  44  to each other based on the simple configuration, without adding a member. Furthermore, since the cut-out portions  243  have the above-described configuration, even if the connector housing  24  shrinks, it is difficult for the sealing resin  44  to escape from the cut-out portions  243 , and the restraint points are stably maintained. Thus, the connection between the connector housing  24  and the sealing resin  44  can be firmly maintained. 
     Fifth Embodiment 
       FIG. 9  is a schematic cross-sectional view illustrating a fifth embodiment of the present invention. As illustrated in  FIG. 9 , the resin-sealed in-vehicle electronic control device  5  mainly includes a circuit board  11 , a connector housing  21 , a sealing resin  41 , and an elastic member  55 . The resin-sealed in-vehicle electronic control device  5  is different from that in the first embodiment in that the elastic member  55  is included. Configurations of the circuit board  11 , the connector housing  21 , and the sealing resin  41 , and a method of forming the resin-sealed in-vehicle electronic control device  5  are the same as those in the first embodiment. Thus, the same elements are denoted by the same reference signs, and the description of the first embodiment is incorporated by reference therefor. 
     The elastic member  55  covers at least a part of an externally exposed portion at a boundary between the connector housing and the sealing resin. Specifically, for example, as illustrated in  FIG. 9 , the elastic member  55  can be provided to tightly adhere to both the connector housing  21  and the sealing resin  41  and entirely cover an externally facing portion (externally exposed portion  75 ) of the boundary. 
     As a material for forming the elastic member  55 , a material having excellent adhesion to the connector housing  21  and the sealing resin  41  is preferable. Examples of the elastic member  55  include low elastic members such as silicone rubber. 
     As described above, since the resin-sealed in-vehicle electronic control device  5  has the above-described configuration, it is possible to securely fix the connector housing  21  and the sealing resin  41  to each other based on the simple configuration, without adding a member. Furthermore, since the boundary is covered by the elastic member  55 , it is possible to improve sealability so as to, for example, cause no gap in the boundary and prevent moisture from getting into the inside of the device even if the connector housing  21  and the sealing resin  41  are peeled off. In addition, since the elastic member  55  is included, it is possible to suppress excessive concentration of stress in the through holes  213 , for example, when an external terminal is connected to the connector housing  21 . As a result, it is possible to prevent the connector housing  21  from being damaged. 
     The present invention is not limited to the configurations of the above-described embodiments, but is intended to cover all modifications falling within the spirit and scope as defined in the claims. 
     For example, it has been described in the above-described embodiments that each of the resin-sealed in-vehicle electronic control devices  1  to  5  includes either the through holes  213  or  223  or the cut-out portions  233  or  243 , but the resin-sealed in-vehicle electronic control device may include both the through holes and the cut-out portions in a mixed manner. 
     In addition, it has been described in the fifth embodiment that the elastic member  55  entirely covers the externally facing portion (externally exposed portion  75 ) at the boundary between the connector housing  21  and the sealing resin  41  in the resin-sealed in-vehicle electronic control device  5 , but the elastic member  55  may partially cover the externally facing portion at the boundary in the resin-sealed in-vehicle electronic control device. 
     REFERENCE SIGNS LIST 
     
         
           1  to  5  resin-sealed in-vehicle electronic control device 
           11  circuit board 
           21  to  24  connector housing 
           41  to  44  sealing resin 
           211   a  to  241   a  first end surface 
           211   b  to  241   b  second end surface 
           213 ,  223  through hole 
           233 ,  243  cut-out portion