Abstract:
An ignition coil assembly for an engine includes an ignition coil for supplying a voltage to a spark plug, a housing supporting the ignition coil, a driving circuit board disposed on the housing and including a circuit unit controlling the ignition coil, and a center cover protecting the driving circuit board. The ignition coil is electrically connected to the driving circuit board.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority to and the benefit of Korean Patent Application No. 10-2006-0080668 filed in the Korean Intellectual Property Office on Aug. 24, 2006, the entire contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   (a) Field of the Invention 
   The present invention relates to an ignition coil assembly for an engine, and more particularly, to an ignition coil assembly having a driving circuit board and a center cover, which are integrated with each other to prevent contact defect and accidental fire of an ignition coil due to a wiring harness short circuit. 
   (b) Description of the Related Art 
   In a conventional ignition coil assembly, ignition coils are individually mounted on a head cover of an engine and are supplied with electric power through a wiring harness. The wiring harness is generally fixed by a bracket and bolt and protected by a center cover. 
   However, since the ignition coils are installed in a very narrow space, it is very difficult to connect the wiring harness to the ignition coils. 
   The ignition coils may be integrated together and made as one assembly, which must be replaced as a whole, even when only one ignition coil malfunctions. 
   In another conventional ignition coil assembly, individual ignition coils are formed in a separable structure. Lots of components are employed, thereby increasing the production costs. In addition, since the electrical/mechanical coupling force is weak, it is difficult to obtain a desired high level of quality. 
   In both conventional ignition coil assemblies, the space for mounting the ignition coils is small and the chance of a short circuit between the connectors is high. In addition, since the assembling process is complicated, the production cost increases. 
   The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
   SUMMARY OF THE INVENTION 
   An exemplary embodiment of the present invention provides an ignition coil assembly for an engine including an ignition coil for supplying a high voltage to a spark plug, a housing supporting the ignition coil, a driving circuit board disposed on the housing and provided with a circuit unit controlling the ignition coil, and a center cover protecting the driving circuit board. The ignition coil is electrically connected to the driving circuit board. 
   The electrical connection between the ignition coil and the driving circuit board may include a female terminal of the driving circuit board and a male terminal of the ignition coil. 
   The center cover and the driving circuit board may be integrally formed together through an insert injection molding process. 
   The housing and the driving circuit board may be integrally formed together through an insert injection molding process. 
   The center cover, the housing, and the driving circuit board may be integrally formed together through an insert injection molding process. 
   The ignition coil assembly may further include a supporting unit for supporting the male terminal of the ignition coil. 
   The ignition coil may be provided with an opening for filling epoxy. 
   A connector for an external connection may be provided on an end of the driving circuit board, the connector having a plurality of pins. 
   The center cover may be coupled to the ignition coil by a coupling member, such as a bolt, such that the center cover and the ignition coil can be disassembled. 
   The terminal of the driving circuit board may be formed in a plate shape. 
   The ignition coil assembly may further include a terminal box enclosing the terminal of the ignition coil. 
   The ignition coil assembly may further include a terminal cover for preventing the terminal of the ignition coil from being removed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of a center cover portion according to an exemplary embodiment of the present invention. 
       FIG. 2  is a perspective view of an ignition coil according to an exemplary embodiment of the present invention. 
       FIG. 3  is a perspective view of a portion where a terminal of an ignition coil is coupled to a terminal of a driving circuit board according to an exemplary embodiment of the present invention. 
       FIGS. 4A and 4B  are respectively top and side views of a driving circuit board according to another exemplary embodiment of the present invention. 
       FIG. 5  is a partly sectioned perspective view illustrating a terminal portion of an ignition coil according to another exemplary embodiment of the present invention. 
       FIG. 6  is an exploded perspective view of the terminal portion of the ignition coil of  FIG. 5 . 
       FIG. 7  is a perspective view of the terminal portion of the ignition coil, when the terminal portion is assembled. 
       FIG. 8  is a rear perspective view of an ignition coil assembly for an engine according to an exemplary embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings. 
   Referring to  FIG. 1 , a driving circuit board  33  is interposed between a center cover  31  and a housing  35 . The center cover  31  and the housing  35  are illustrated in a state where they are separated from each other. However, at least two of the three parts (center cover  31 , driving circuit board  33 , and housing  35 ) may be integrally formed together. 
   The center cover  31  and the driving circuit board  33  may be integrally formed together through an insert injection molding process. Alternatively, the housing  35  and the driving circuit board  33  may be integrally formed together through an insert injection molding process. Alternatively, the center cover  31 , the housing  35 , and the driving circuit board  33  may be integrally formed together through an insert injection molding process. 
   When the above-mentioned components are integrally formed together through the insert injection molding process, the number of components is reduced and the number of manufacturing processes is reduced, thereby reducing the production cost. 
   Referring to  FIGS. 2 and 3 , in a first exemplary embodiment, a circuit unit  51  and a driving circuit board female terminal box  53  are connected to each other. The circuit unit  51  encloses an ignition coil male terminal ( 43  of  FIG. 2 ). 
   As the female terminal of the driving circuit board is interlocked with the male terminal  43  of the ignition coil  41 , the maintenance of the ignition coils  41  is more effective. That is, when one or more of the ignition coils malfunction, only the malfunctioning ignition coil need to be separated to be repaired or replaced. 
   Referring to  FIG. 8 , the ignition coil  41  is coupled to the housing  35  by a coupling member  47 . 
   In order to prevent the male terminal  43  of the ignition coil  41  from being bent, the male terminal  43  of the ignition coil  41  is covered by a male terminal supporting portion  45 . 
   Referring to  FIGS. 4A and 4B , in another exemplary embodiment, a driving circuit board  61  includes a circuit unit  63 , a connector  65 , through which electric power and external signal are applied, ignition coils controlled by the circuit unit  63 , and terminal portions  67  that are terminal coupled. 
   The connector  65  includes a plurality of pins and is provided on an end of the driving circuit board  61 . The terminals  67  may be male or female terminals, and, in an exemplary embodiment, may be male terminals each formed in a plate shape. 
   Referring to  FIG. 5 , the ignition coil terminal boxes  75  enclose the terminals  73  to prevent them from being insulated by injection of resin. 
   In addition, in order to prevent the female terminals  73  of the ignition coil  71  from being separated upward and away from the ignition coil  71 , as shown in  FIGS. 6 and 7 , a terminal cover  77  may be mounted above the terminals  73  and the terminal boxes  75 . 
   An opening  79  is provided under the terminals  73  of the ignition coil  71  to fill the resin up in the bottom during the injection of the resin. 
   The following will describe the coupling of the ignition coil to the housing. 
   As shown in  FIG. 8 , the ignition coils  41 ,  71  are individually coupled to the housing  35 ; they can thus be individually repaired or replaced during maintenance after being separated independently from the others. 
   The coupling portion  49  may include a bolt so that the separation of the ignition coil  41  can be easily accomplished. 
   As described above, the ignition coil assembly of the present invention has the following effects: 
   Since the assembly is formed in a module type and a wiring harness is not used, the number of components and the weight can be reduced, thereby reducing the production cost. Furthermore, since the ignition coil assembly has a simple structure, the shape of the ignition coil, which up to now has had various designs for different vehicles, can be standardized. Since the ignition coils are designed to be individually coupled and uncoupled to the housing, maintenance can be easily performed. For example, when one of the ignition coils malfunctions, the relevant ignition coil is dissembled from the housing and repaired or replaced. Therefore, the maintenance cost can be reduced. 
   While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.