Abstract:
There is provided a joint fastening structure which is commonly used as a fastening portion of an internal combustion engine main body and a transmission case and a fastening portion of the internal combustion engine main body and an accessory, wherein a threaded component passes through the transmission case and the internal combustion engine main body so as to be integrally fastened to internal threads in the accessory.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a joint fastening structure for an automotive power plant fastening portion in which an accessory is jointly fastened to the fastening portion. 
     2. Description of the Related Art 
     In a conventional power plant in which a transmission is integrally connected to an end face of an internal combustion engine on an output shaft end side, since an accessory needs to be disposed within a predetermined narrow space in an engine compartment, the accessory is secured to the housing at a portion of the internal combustion engine main body which is contiguous with the transmission with threaded components such as bolts and screws, and the housing is fastened to the cylinder block with threaded components. In addition, the cylinder block and the transmission case are fastened together with threaded components. 
     In a mounting structure as described above, however, since the fastening portion where the accessory is mounted on the housing and the fastening portion where the housing is mounted on the internal combustion engine main body interfere with each other, there is caused a drawback that the disposition of the accessory is limited whereby the degree of freedom in layout of the accessory is reduced. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an improved automotive power plant fastening portion which has overcome the difficulty, and according to a first aspect of the invention, there is provided a joint fastening structure for an automotive power plant fastening portion which is commonly used as a fastening portion of an internal combustion engine main body and a transmission case and a fastening portion of said internal combustion engine main body and an accessory, the joint fastening structure being characterized in that a threaded component passes through the transmission case and the internal combustion engine main body so as to be integrally fastened to internal threads in the accessory. 
     According to the first aspect of the invention, with the aforesaid structure, since the threaded component is inserted from the transmission case side, the internal combustion engine main body and the transmission case can easily be fastened together without being influenced by the mounting configuration of the accessory to the housing and the other accessories. 
     In addition, since the accessory is jointly fastened to the internal combustion engine and the transmission which constitute the automotive power plant with the threaded component which integrally combines the internal combustion engine with the transmission, the fastening man-hours and number of fastening components can be reduced, and this leads to reduction in cost. 
     In addition, according to a second aspect of the invention, portions at which the threaded component passes through the transmission case and the internal combustion engine main body are flanges. According to the construction of the second aspect of the invention, since the flange portions of the internal combustion engine main body and the transmission case are highly rigid, in addition to the advantage provided by the first aspect of the invention, there is provided an advantage that the fastening strength can be increased. 
     Furthermore, according to a third aspect of the invention, the threaded component is disposed in the vicinity of a mating surface between the cylinder block and the oil pan. According to the construction of the third aspect of the invention, since the threaded component for use in attaching the accessory is allowed to pass through the highly rigid portion in the vicinity of the mating surface between the cylinder block and the oil pan, in addition to the advantages provided in accordance with the first and second aspects of the invention, there is further provided an advantage that the fastening strength of the accessory relative to the internal combustion engine main body and the transmission case can further be increased. 
     In addition, while the accessory itself tends to be heated by virtue of heat conducted from the cylinder block of the internal combustion engine, according to a fourth aspect of the invention, a cooling water pipe member communicating with a radiator is disposed along the vicinity of the accessory. Thus, in addition to the advantages provided in accordance with the first, second and third aspects of the invention, there is provided an advantage that the accessory can be cooled by cooling water to thereby improve the durability since the temperature of the cooling water passing through the interior of the cooling water pipe member is lower than that of the accessory. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of an embodiment of the invention; 
     FIG. 2 is a view as seen in a direction indicated by an arrow II in FIG. 1; and 
     FIG. 3 is a view taken along the line III—III in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the invention illustrated in FIGS. 1 to  3  will be described below. 
     An automotive power plant  1  mounted at a front portion of a vehicle body of a passenger car, not shown, is an in-line four-cylinder four-stroke-cycle engine with DOHC (double overhead camshafts), and as shown in FIG. 1, the automotive power plant  1  comprises an internal combustion engine  2  and a transmission  3 . In a main body of the internal combustion engine  2 , a cylinder block  4  and an oil pan  5  are brought into abutment with each other at a mating surface  6 , an upper surface of the cylinder block  4  and a lower face of a cylinder head  29  are brought into abutment with each other. The cylinder block  4 , the oil pan  5  and the cylinder head  29  are combined with each other with bolts or stud bolts which are not shown. 
     In addition, an end face of a flange  9  of a case of the transmission  3  is brought into abutment with end faces (right end faces as viewed in FIG. 1, or portions of FIG. 3 where many dots are provided and many doted lines are caused to intersect with each other) of a flange  7  of the cylinder block  4  and a flange  8  of the oil pan  5 . A housing flange  11  of a starter motor  10  is brought into abutment with the other end face (a left end face as viewed in FIG. 1) of the flange  7  of the cylinder block  4 . Then, a distal externally threaded portion  13  of a bolt  12  passing through a bolt hole  9   a  in the flange  9  of the transmission  3  and a bolt hole  7   a  in the flange  7  of the cylinder block  4  from right to left is fastened into an internally threaded hole  14  in the housing flange  11  of the starter motor  10 , whereby the transmission  3 , the cylinder block  4  and the starter motor  10  are constructed so as to be integrally jointly fastened together with the bolt  12 . 
     Furthermore, as shown in FIG. 1, a bolt  15  passes through an upper portion of the flange  9  of the case of the transmission  3  from right to left to be fastened into a bolt hole  7   b  in an upper portion of the flange  7  of the cylinder block  4  (refer to FIGS.  2  and  3 ). And, a bolt  16  passes through a bolt hole  8   a  in a lower portion of the flange  8  of the oil pan  5  (refer to FIGS. 2 and 3) from left to right to be fastened into a lower portion of the flange  9  of the case of the transmission  3 . Bolts, not shown, other than but similar to the bolt  15  or bolt  16  are fastened along the full circumference of the transmission  3  at required intervals. 
     Moreover, as shown in FIG. 1, the housing flange  11  of the starter motor  10  is brought into abutment with a bottom portion  18  of a main body  17  of the starter motor  10  from left, and as shown in FIG. 2, protruding lugs  20  are integrally provided on a top portion  19  of the main body  17  of the starter motor  10  diametrically across the center of the main body  17 . Then, as shown in FIG. 1, an externally threaded portion  22  of a machine screw  21  passing through the protruding lug  20  from left to right is fastened into an internally threaded portion  23  of the housing flange  11  of the starter motor  10 . 
     Moreover, as shown in FIG. 2, a magnet switch  24  is integrally assembled the main body  17  of the starter motor  10 . 
     In addition, as illustrated in FIG. 1, an air conditioner compressor  25  is integrally mounted on the cylinder block  4  at a position below the lower surface of the cylinder block  4  on a left end side thereof with a mounting member, not shown. And, a cooling water pump  26  is integrally mounted on the cylinder block  4  with a mounting member, not shown, at a position above the air conditioner compressor  25  and on this side of the cylinder block  4  as viewed in FIG.  1 . Further, an ACG  27 , which is an alternate current generator, is integrally mounted on the cylinder block  4  with a mounting member, not shown, at a position above the cooling water pump  26 . The cooling water pump  26  and an upper right-hand side portion (as viewed in FIG. 1) of the cylinder block  4  are connected to each other via a cooling water pipe  28  so as to provide a communication therebetween, the cooling water pipe  28  being a cooling water pipe member which connects to a radiator, not shown. 
     The embodiment illustrated in FIGS. 1 to  3  is constructed as described above, and at the position where the starter motor  10  is mounted on the cylinder block  4 , the housing flange  11  of the starter motor  10  is integrally jointly fastened to the flange  7  of the cylinder block  7  and the flange  9  of the transmission  3  with the bolts  12  which pass through the bolt hole  9   a  in the flange  9  of the transmission  7  and the bolt hole  7   a  in the flange  7  of the cylinder block  4  from right to left as viewed in FIG. 1 to be fastened into the internally threaded hole  14  in the housing flange  11  of the starter motor  10 . Therefore, the cylinder block  4  and the transmission  3  need to be fastened together with no other bolt, whereby the fastening man-hours and number of fastening bolts can be reduced, this leading to reduction in production costs. 
     Furthermore, since the bolt  12  is fastened from the transmission  3  side toward the cylinder block  4  side of the internal combustion engine  2 , the fastening work of the bolt  12  can easily be implemented without any interference with the starter motor  10 , the magnet switch  24  and the cooling water pipe  28 . 
     Moreover, while the starter motor  10  tends to be heated to a high temperature when receiving heat from the cylinder block  4  which is heated to a high temperature and heat from the atmosphere within the engine compartment, since the temperature of the cooling water in the cooling water pipe  28  is lower than the temperatures of the cylinder block  4  and the starter motor  10  irrespective of the running condition of the internal combustion engine  2 , the starter motor  10  is cooled by the cooling water running through the cooling water pipe  28 , the durability being thereby increased. 
     While only certain embodiments of the invention have been specifically described herein, it will apparent that numerous modifications may be made thereto without departing from the spirit and scope of the invention.