Abstract:
A tensioner that controls tension of a loop-shaped connecting body linking an output portion of an engine body and an output-input portion of a motor generator is fixed to the motor generator.

Description:
INCORPORATION BY REFERENCE 
   The disclosure of Japanese Patent Application No. 2004-116618 filed on Apr. 12, 2004 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a mounting structure of a motor generator for an internal combustion engine in which the motor generator is attached to an engine body of the internal combustion engine and coupled to and driven by the output thereof. More particularly, the invention relates to such a mounting structure for which a tensioner, which applies tension to a power transmission belt coupled to the internal combustion engine, is attached to the motor generator. 
   2. Description of the Related Art 
   Art is known in which the output of an engine is utilized to drive a water pump, an air conditioner compressor, an alternator, and the like. Moreover, a motor generator is sometimes adopted in place of an alternator, and used to provide torque assistance. In this case, the motor generator is driven by the output of the engine instead of the alternator. 
     FIG. 3  shows a known motor generator mounting structure e of this type. A pulley  12  is provided on an engine block  10  and rotated by a crank shaft of the engine. 
   In addition, a water pump  14  is provided on one side of the engine block  10  (more specifically, the right side as shown in  FIG. 3 ). The water pump  14  is a coolant pump that uses rotation of a pulley  16  to circulate coolant to the engine and a radiator (not shown). 
   A motor generator  18  is disposed next to the water pump  14 . The motor generator  18  uses torque of the engine to generate electricity for recharging a battery (not shown), and, in addition, assists engine output torque when necessary by rotating an output shaft of the engine (namely, the crank shaft). The motor generator  18  has a rotating shaft to which a pulley  20  is attached. Moreover, an air conditioner compressor  22  is disposed near to the water pump  14  and the motor generator  18 . The compressor  22  is driven by a pulley  24 . 
   A belt  26  is wound around the pulleys  12 ,  16 ,  20  and  24 . Accordingly, driving force of the pulley  12  is used to drive the water pump  14 , the motor generator  18 , and the compressor  22 . 
   Note that, in order to transmit driving force it is essential that the belt  26  is pressed against the pulleys  12 ,  16 ,  20  and  24  so that it does not slip. To achieve this, a tensioner  28  is provided that applies tensioning force (tension) to the belt  26 . 
   The tensioner  28  includes a body  34 , and a pair of rollers  36   a  and  36   b.  The pair of rollers  36   a  and  36   b  apply tension to the belt  26  by pressing the outer sides thereof. The tensioner  28  is fixed at one side to a boss of the engine block  10  using a bracket  38   a,  and at the other side to an external wall of the water pump  14  using a bracket  38   b.    
   In the previously described structure, provision of the tensioner  28  enables a desired amount of tension to be applied to the belt  26 . Accordingly, driving force can be reliably transmitted using the belt  26 . 
   Note that, the tensioner  28  is highly versatile, and may be used with various different types of engines. However, in the case of another engine, the position of the boss to which the tensioner can be fixed is different, and thus it is necessary to manufacture a bracket to match. Moreover, if a suitable boss is not provided on the engine block, it is necessary to make changes to the engine block itself. 
   It should be noted that there are various ways in which tensioners can be fitted to an engine. For example, Japanese Patent Laid-Open Publication No. 2003-201857 discloses a configuration in which a tensioner is attached to an oil pump that is driven by an engine via a chain. The tensioner applies tension to the chain. 
   SUMMARY OF THE INVENTION 
   The invention provides a motor generator mounting structure for an internal combustion engine that enables a tensioner to be efficiently attached. 
   A first aspect of the invention relates to a motor generator mounting structure for an internal combustion engine including an engine body including a drive shaft and an output portion connected to the drive shaft, a motor generator which is attached to the engine body and which includes a drive shaft and an output-input portion connected to the drive shaft, a loop-shaped connecting body that links the output portion of the engine body and the output-input portion of the motor generator, and a tensioner which controls tension of the loop-shaped connecting body and which is fixed to the motor generator. 
   According to the foregoing structure, since the tensioner is attached to the motor generator, there is no need to attach the tensioner to the engine body, which offers enhanced versatility. Also, this structure provides an advantage that if the loop-shaped connecting body is a belt or the like, its winding angle can be easily maintained at a predetermined angle or more. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and/or further objects, features and advantages of the invention will become more apparent from the following description of preferred embodiment with reference to the accompanying drawings, in which like numerals are used to represent like elements and wherein: 
       FIG. 1  shows the configuration of an embodiment of the invention; 
       FIG. 2  illustrates the attachment structure of a motor generator and a tensioner; and 
       FIG. 3  shows a known motor generator mounting structure. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, an embodiment of the invention will be described with reference to the drawings. 
     FIG. 1  shows an area around structural elements like an engine block and a motor generator to which a tensioner according to the invention is attached. 
   The structure shown in  FIG. 1 , like the known example of  FIG. 3 , includes an engine block  10 , a water pump  14 , a motor generator  18 , and an air conditioner compressor  22 , as well as respective pulleys  12 ,  16 ,  20  and  24  which are attached thereto. A belt  26  is wound around the pulleys  12 ,  16 ,  20  and  24 . Accordingly, driving force of the pulley  12  is utilized to drive the water pump  14 , the motor generator  18 , and the compressor  22 . 
   A tensioner  28  for the belt  26  is provided in the vicinity of the motor generator  18 , and applies tensioning force (tension) in a similar manner to the previously described known art. 
   Further, as shown in  FIG. 2 , the tensioner  28  includes a main body  34 , and a pair of rollers  36   a  and  36   b.  An attachment  40  is provided in a central portion of the main body  34  between the rollers  36   a  and  36   b,  and a base portion of the attachment  40  is welded to the base  34 . A pair of bolt holes  42   a  and  42   b  are provided in a protruding portion of the attachment  40  that protrudes from the main body  34 . It should be noted that the attachment  40  may be fixed to the main body  34  by methods other than welding, such as by bolting. 
   The motor generator  18  is provided with a pair of bosses  44   a  and  44   b,  which are positioned so as to correspond with the bolt holes  42   a  and  42   b.  Accordingly, as shown in  FIG. 1 , the tensioner  28  is fixed to the motor generator  18  by aligning and bolting together the bosses  44   a  and  44   b  and the bolt holes  42   a  and  42   b.    
   Further, one side of the motor generator  18  is fixed to the engine block  10 , and the other side is movably attached by a fixing portion  50  to an attachment point which would be used, in the case of the known art, to attach an alternator. The fixing portion  50  includes a long hole and a bolting mechanism for bolting a bolt in the long hole. The fixing portion  50  allows the entire motor generator  18  to be attached to the engine block  10  such that an attachment angle of the motor generator  18  can be changed centering on an axis point at the engine block  10  edge side. Note that, it is possible to adjust the tension of the belt  26  by adjusting the attachment position of the motor generator  18  in the fixing portion  50 . 
   Accordingly, in this embodiment, the tensioner  28  is fixed to the motor generator  18  rather than the engine block  10 , and there is no need to provide a bracket for attachment to the engine block  10 . As a result, the embodiment can be easily applied to different engines with different boss positions or no suitable bosses since the tensioner  28  is fixed to the motor generator  18 . Accordingly, the previously discussed attachment related problems of the known art are not encountered. The embodiment thus offers outstanding versatility, and provides an efficient structure that eliminates the need to modify unnecessary components, or the like, since the tensioner  28  is fixed to the motor generator  18 . 
   In addition, it is preferable if the tensioner  28  is fixed to the motor generator  18  first, and then both elements are attached to the engine block  10  as a single component. Accordingly, if the tensioner  28  is fixed to the motor generator  18  in advance, when these elements are attached to the engine block  10 , the operation can be performed with great ease in the same way as when just the motor generator  18  is attached. Furthermore, if the motor generator  18  and the tensioner  28  are attached separately, it is necessary to provide a degree of installation space to prevent interference of the motor generator  18  and the tensioner  28  from occurring. Accordingly, enough space to satisfy this requirement must be left. However, if the tensioner  28  and the motor generator  18  are fixed together to start with, the installation space that must be left is only that required for attachment of a single integrated component. As a result, it is possible to reduce the amount of installation space that must be left by a corresponding extent. 
   It should be noted that if the winding angle of the belt  26  with respect to the pulley  20  of the motor generator  18  becomes less than 180 degrees, there is a possibility that the belt  26  will slip on the pulley  20 . However, according to this embodiment, the position of the tensioner  28  etc. with respect to the pulley  20  can be determined in advance, thus making it easy to set the winding angle of the belt  26  at 180 degrees or more. 
   In addition, if multiple bosses for attachment of the tensioner  28  are provided at predetermined distances apart around the entire circumference of the motor generator  18 , it is possible to attach the tensioner  28  from various different directions. Accordingly, it is possible to improve attachment flexibility. 
   While the invention has been described with reference to preferred embodiments thereof, it is to be understood that the invention is not limited to the preferred embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements other than described above. In addition, while the various elements of the preferred embodiments are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the invention.