Patent Publication Number: US-9885359-B2

Title: Motor-driven compressor

Description:
TECHNICAL FIELD 
     The present invention relates to a motor-driven compressor. 
     BACKGROUND ART 
     Conventional motor-driven compressors (hereinafter simply referred to as compressors) are disclosed in Japanese Patent Laid-Open Nos. 2006-9688 and 2010-38014. 
     The compressor disclosed in Japanese Patent Laid-Open No. 2006-9688 comprises a rotation shaft, a motor mechanism capable of rotating the rotation shaft, a front housing member accommodating the motor mechanism, a rear housing member closing an opening of the front housing member, and a compression mechanism fixed to the front and rear housing members. The front housing member includes a suction pressure region, and the rear housing member includes a discharge pressure region. 
     The compression mechanism of Japanese Patent Laid-Open No. 2006-9688 includes a rotor, five vanes, a cylinder formed into a cylindrical shape and enclosing the rotor, a front side block, and a rear side block. The rotor is rotatable by the rotation shaft and provided with five vane grooves. The vanes are disposed advanceably and retractably in the respective vane grooves. The front side block and the rear side block close opposite ends of the cylinder. The cylinder and the front and rear side blocks form a cylinder chamber. 
     The compressor disclosed in Japanese Patent Laid-Open No. 2010-38014 comprises a rotation shaft, a motor mechanism capable of rotating the rotation shaft, a motor housing member accommodating the motor mechanism, a compressor housing member closing an opening of the motor housing member, a front housing member fixed to the compressor housing member, and a compression mechanism enclosed in the compressor housing member. The motor housing member includes a discharge pressure region, and the front housing member includes a suction pressure region. 
     The compression mechanism of Japanese Patent Laid-Open No. 2010-38014 includes a rotor, plural vanes, a cylinder block formed into a cylindrical shape and enclosing the rotor, a rear side block formed integrally with the compressor housing member and closing one end of the cylinder block, and a front side block closing the other end of the cylinder block. The rotor is rotatable by the rotation shaft and provided with plural vane grooves. The vanes are disposed advanceably and retractably in the respective vane grooves. The cylinder block and the front and rear side blocks form a cylinder chamber. 
     According to the compressor of Japanese Patent Laid-Open No. 2006-9688, however, because the suction pressure region in the front housing member is formed by fixing a partition wall member, which is a different member from the cylinder, to the front and rear housing members, assembly work is complicated. According to the compressor of Japanese Patent Laid-Open No. 2010-38014, because the front and rear side blocks are interposed between the motor housing member and the front housing member, assembly work is complicated. Furthermore, in these compressors, due to a large number of components, high costs are required for machining, managing, and assembling individual components, and besides, it is necessary to increase the number of sealing positions or employ seals with high pressure tightness in order to secure sealing capability. Consequently, it is difficult to reduce manufacturing costs in these compressors. 
     The present invention has been made in view of the conventional circumstances described above, and it is an object of the invention to provide a motor-driven compressor capable of realizing reduction in manufacturing costs. 
     SUMMARY OF THE INVENTION 
     A motor-driven compressor according to the present invention comprises: 
     a rotation shaft; 
     a motor mechanism capable of rotating the rotation shaft; 
     a first housing formed into a bottomed cylindrical shape and accommodating the motor mechanism, the first housing being provided with an inlet port and including a suction pressure region; 
     a second housing joined to an open side of the first housing, the second housing being provided with an outlet port and including a discharge pressure region; and 
     a compression mechanism fixed to and supported by the second housing so as to partition the suction pressure region from the discharge pressure region, the compression mechanism being driven by the rotation shaft and including at least one compression chamber. The compression chamber is connected to the suction pressure region and the discharge pressure region and configured such that refrigerating gas sucked into the suction pressure region is compressed in the compression chamber and discharged to the discharge pressure region. The contour of the compressor is formed by the first housing and the second housing. The suction pressure region in the first housing is hermetically closed, or sealed from outside at a position where the first housing and the second housing are joined together. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a motor-driven compressor according to a first embodiment taken in an axial direction of a rotation shaft. 
         FIG. 2  is a sectional view of the motor-driven compressor according to the first embodiment taken in a direction perpendicular to the axial direction. 
         FIG. 3  is an exploded perspective view showing a cup member and a cover member of the motor-driven compressor according to the first embodiment. 
         FIG. 4  is a sectional view of a motor-driven compressor according to a second embodiment taken in an axial direction of a rotation shaft. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The first and second embodiments which embody the present invention will be described below with reference to the drawings. 
     (First Embodiment) 
     As shown in  FIG. 1 , a motor-driven compressor (hereinafter simply referred to as a compressor) according to the first embodiment comprises a rotation shaft  19 , a motor mechanism  3 , a first housing  1 , a second housing  9 , and a compression mechanism  13 . Hereinafter, in  FIG. 1 , the side on which the first housing  1  is disposed is defined as the front side of the compressor, while the side on which the second housing  9  is disposed is defined as the rear side of the compressor. 
     The first housing  1  is formed into a bottomed cylindrical shape and extends rearward from the front side of the compressor in an axial direction of the rotation shaft  19 , i.e. along an axis  0  of the rotation shaft  19 . The front end of the first housing  1  is closed by a bottom wall  1   a , and the rear end thereof is provided with an opening  1   b . The first housing  1  includes a motor chamber  1   c , which serves as a suction pressure region. As shown in  FIG. 2 , the first housing  1  includes a cylindrical portion  1   d  formed into a cylindrical shape and a bulging portion  1   e  bulging outward from the cylindrical portion  1   d . As shown in  FIG. 1 , the first housing  1  is provided with an inlet port  1   f , through which the motor chamber  1   c  communicates with outside. The inlet port  1   f  is connected to an evaporator of a vehicle air-conditioning apparatus via piping. 
     The motor mechanism  3  is disposed in the motor chamber  1   c  and includes a stator  15  and a motor rotor  17 . The stator  15  is fixed to the inner circumferential surface of the first housing  1 . A hermetic terminal  16  for maintaining the motor chamber  1   c  in a hermetic state is provided in parallel to the axial direction at the bulging portion  1   e  of the first housing  1 . The outer end of the hermetic terminal  16  is connected to an electric power supply device (not shown), and the inner end of the hermetic terminal  16  is connected to the stator  15  by lead wires  16   a  via a cluster block  2 . The motor rotor  17 , through which the rotation shaft  19  extending in the axial direction is inserted, is disposed in the stator  15 . A shaft support portion  1   g  is formed on the bottom wall  1   a  of the first housing  1  so as to project in the axial direction, and a bearing device  21  is provided in the shaft support portion  1   g . The front end portion of the rotation shaft  19  is supported by the bearing device  21 . 
     The second housing  9  is fixed to the rear end of the first housing  1  with plural bolts  14 . The second housing  9  is formed into a bottomed cylindrical shape. The rear end of the second housing  9  is closed by a bottom wall  9   d , and the front end thereof is provided with an opening  9   e . The periphery of the opening  9   e  of the second housing  9  abuts the periphery of the opening  1   b  of the first housing  1  with an O-ring  4  interposed therebetween, and thereby, the first housing  1  and the second housing  9  are closed. A flat-shaped side plate  5 , which extends radially in a direction perpendicular to the axial direction, is fitted into the opening  9   e  of the second housing  9 . An O-ring  23  is provided between the outer circumferential surface of the side plate  5  and the inner circumferential surface of the second housing  9 . A block  35  is fixed to the side plate  5 . 
     A cup member  7  formed into a bottomed cylindrical shape is fixed to the front face of the side plate  5  with plural bolts  25 . The cup member  7  includes a bottom portion  27  and a cylinder forming portion  29 . The bottom portion  27  is disposed closer to the motor rotor  17  than the cylinder forming portion  29  and extends in the radial direction. The bottom portion  27  is provided with a shaft hole  27   a , through which the rotation shaft  19  is inserted. Plating (not shown) is applied to the shaft hole  27   a  in order to enhance smooth rotational sliding of the rotation shaft  19 . 
     The cylinder forming portion  29  is integrally formed with the bottom portion  27  and extends cylindrically in the axial direction. By fixing the cup member  7  to the side plate  5  with the bolts  25 , a cylinder chamber  31  is formed inside the cup member  7 . As shown in  FIG. 2 , the cross section of the cylinder chamber  31  taken in a direction perpendicular to the axial direction has a perfectly round shape. The axis of the cylinder chamber  31  is offset from the axis O. Plating (not shown) is applied to the inner surfaces at the front and rear ends of the cylinder chamber  31  and the inner circumferential surface of the cylinder chamber  31  in order to enhance smooth rotational sliding of a rotor  45  and vanes  47   a  and  47   b , which will be described later. 
     Also, as shown in  FIG. 1 , a suction passage  33 , which opens in the axial direction and communicates with the motor chamber  1   c,  is formed through the bottom portion  27 . The suction passage  33  extends in the axial direction in the cylinder forming portion  29  and, as shown in  FIG. 2 , communicates with the cylinder chamber  31  via a suction port  33   a , which is provided in a recessed manner in the cylinder forming portion  29 . 
     As shown in  FIG. 3 , a discharge pressure space  37  is provided in a recessed manner in the cylinder forming portion  29  so as to open to the outer circumferential side. As shown in  FIGS. 1 and 2 , the discharge pressure space  37  communicates with the cylinder chamber  31  via a discharge port  37   a , which is formed through the cylinder forming portion  29 . In the discharge pressure space  37 , a discharge reed valve  39 , which opens and closes the discharge port  37   a , and a retainer  41 , which regulates an opening degree of the discharge reed valve  39 , are fixed to the cylinder forming portion  29  with a bolt  43 . The discharge pressure space  37  includes a discharge passage  37   b  communicating with an oil separation chamber  35   a , which will be described later. 
     The rotor  45  is provided in the cylinder chamber  31  so as to be rotatable by the rotation shaft  19 . The rotor  45  is press-fitted to the rotation shaft  19  or coupled to the rotation shaft  19  with a key. The cross section of the rotor  45  taken in a direction perpendicular to the axial direction has a perfectly round shape. The axis of the rotor  45  coincides with the axis O. As shown in  FIG. 2 , the rotor  45  is provided with two vane grooves  45   a  and  45   b . The vane grooves  45   a  and  45   b  are parallel to an imaginary reference plane on which the axis  0  lies. The vanes  47   a  and  47   b , which are formed into a flat-plate shape, are disposed advanceably and retractably in the respective vane grooves  45   a  and  45   b . The spaces surrounded by the bottom faces of the vanes  47   a  and  47   b  and the vane grooves  45   a  and  45   b  are defined as back pressure chambers  49   a  and  49   b , respectively. Two compression chambers  50   a  and  50   b  are formed by the front surface of the cylinder chamber  31 , the inner circumferential surface of the cylinder chamber  31 , and the rear surface of the cylinder chamber  31  as well as the outer circumferential surface of the rotor  45  and the respective vanes  47   a  and  47   b.    
     As shown in  FIG. 1 , an annular groove  27   b  is provided in a recessed manner around the axis O at the rear face of the bottom portion  27  of the cup member  7 . Furthermore, an annular groove  5   a  is provided in a recessed manner around the axis O at the front face of the side plate  5  so as to face the annular groove  27   b  in the front-rear direction. 
     An O-ring  51  is provided between the cylinder forming portion  29  and the front face of the side plate  5 . A discharge chamber  9   a  is formed between the second housing  9  and the side plate  5 . The discharge chamber  9   a  serves as a discharge pressure region. The second housing  9  is provided with an outlet port  9   b , through which the discharge chamber  9   a  communicates with outside. The outlet port  9   b  is connected to a condenser of the vehicle air-conditioning apparatus via piping. 
     The oil separation chamber  35   a  is formed into a columnar shape and extends perpendicularly to the axial direction in the block  35 . A cylindrical member  53  formed into a cylindrical shape is fixed to the oil separation chamber  35   a . The upper end of the cylindrical member  53  opens to the discharge chamber  9   a , and the lower end of the oil separation chamber  35   a  opens to the discharge chamber  9   a  through an oil outlet  35   b . Passages  5   b  and  35   c  are formed through the side plate  5  and the block  35  so as to allow the discharge passage  37   b  to communicate with the oil separation chamber  35   a.  The oil separation chamber  35   a  and the cylindrical member  53  constitute an oil separator. 
     The side plate  5  is provided with a shaft hole  5   c , through which the rotation shaft  19  is inserted. Plating (not shown) is applied to the shaft hole  5   c  in order to enhance smooth rotational sliding of the rotation shaft  19 . The rear end portion of the rotation shaft  19  is supported by the shaft hole  5   c . In this manner, both ends of the rotation shaft  19  are supported by the bottom wall  1   a  of the first housing  1  and the shaft hole  5   c  of the side plate  5 , respectively, and thereby the rotation shaft  19  is suitably rotatable. 
     An oil supply chamber  55  is formed between the side plate  5  and the block  35 . The oil supply chamber  55  communicates with the shaft hole  5   c . An oil groove  9   c  is provided in a recessed manner at the bottom portion of the side plate  5 . The oil groove  9   c  communicates with the discharge chamber  9   a . A first passage  5   d  is formed in the side plate  5 . The first passage  5   d  communicates with the oil groove  9   c  and extends upward so as to approach the axis O. A second passage  5   e  and a third passage  5   f  are also formed in the side plate  5 . The second passage  5   e  allows the oil supply chamber  55  to communicate with the upper end of the first passage  5   d , and the third passage  5   f  allows the oil supply chamber  55  to communicate with the annular groove  5   a . A throttle member  57  is fitted into the first passage  5   d . The throttle member  57  includes a throttle passage  57   a  extending therethrough, the diameter of which is smaller than that of the first passage  5   d.    
     As shown in  FIG. 3 , a cover member  11  is provided on the outer circumference of the cup member  7 . The cover member  11  has an inner flange  11   a  on which three fixing pieces  11   b  are formed. As shown in  FIG. 1 , the cover member  11  is fixed to the cup member  7  by screwing three bolts  60  into the respective fixing pieces  11   b  in the axial direction. Between the outer circumferential surface of the cylinder forming portion  29  of the cup member  7  and the inner circumferential surface of the cover member  11 , O-rings  59  and  61  are provided. The O-rings  59  and  61  are disposed in the front-rear direction with the discharge pressure space  37  interposed therebetween. In this way, as shown in  FIG. 2 , the cover member  11  surrounds the cylinder forming portion  29  of the cup member  7  so as to separate the discharge pressure space  37  from the motor chamber  1   c . The rotor  45 , the vanes  47   a  and  47   b , the cup member  7 , the side plate  5 , and the cover member  11  constitute the compression mechanism  13 . 
     In this compressor, when electric power is supplied to the stator  15  shown in  FIG. 1 , the motor mechanism  3  starts operation and the rotation shaft  19  rotates around the axis O. The compression mechanism  13  then operates and the rotor  45  rotates in the cylinder chamber  31 , which is formed by the cup member  7  and the side plate  5 . During the rotation of the rotor  45 , the volume of the respective compression chambers  50   a  and  50   b  increases and decreases repeatedly. Therefore, in the compression chambers  50   a  and  50   b , a suction phase for introducing low-pressure refrigerating gas from the motor chamber  1   c  via the suction passage  33  and the suction port  33   a  takes place. This suction phase is followed by a compression phase in which the refrigerating gas is compressed in the compression chambers  50   a  and  50   b . The compression phase is then followed by a discharge phase in which the compressed high-pressure refrigerating gas in the compression chambers  50   a  and  50   b  is discharged to the discharge chamber  9   a  through the discharge port  37   a , the discharge pressure space  37 , and the passages  5   b  and  35   c . In this way, air-conditioning of a vehicle interior is carried out. 
     At this time, due to a centrifugal force, lubricating oil is separated from the high-pressure refrigerating gas discharged into the oil separation chamber  35   a  through the passages  5   b  and  35   c . The lubricating oil is accumulated in the discharge chamber  9   a . Then, due to a high pressure in the discharge chamber  9   a , the lubricating oil is supplied to the annular groove  5   a , flowing through the oil groove  9   c , the throttle passage  57   a  of the throttle member  57 , the first passage  5   d , the second passage  5   e , the oil supply chamber  55 , and the third passage  5   f . Because the annular groove  5   a  communicates with the back pressure chambers  49   a  and  49   b,  back pressure is applied to the vanes  47   a  and  47   b . Therefore, the vanes  47   a  and  47   b  are suitably urged against the inner circumferential surface of the cylinder chamber  31 , and thereby compression work is performed with high efficiency. 
     In this compressor, since the compression mechanism  13  is fixed as a unit to the second housing  9 , not to the first housing  1 , assembly work is easy. That is, it is sufficient to merely fix the compression mechanism  13  to the second housing  9  and then assemble the first housing  1 . The motor mechanism  3  may be assembled to the compression mechanism  13  via the rotation shaft  19  before the compression mechanism  13  is fixed to the second housing  9 , or, the compression mechanism  13  may be fixed to the second housing  9  first, and then the motor mechanism  3 , and thereafter the first housing  1 , may be assembled. 
     Furthermore, since this compressor comprises less number of components, it is possible to reduce the costs for machining, managing, and assembling individual components. In addition, since the compression mechanism  13  is not exposed outside and the suction pressure region with low pressure is disposed at the position where the first housing  1  and the second housing  9  are joined together, external leakage of the refrigerating gas from the compression mechanism  13  can be easily sealed with a simple structure. 
     More specifically, in this compressor, the compression mechanism  13  includes the cup member  7  formed into a bottomed cylindrical shape, and by simply fixing the cup member  7  to the side plate  5 , i.e., to a single piece, the cylinder chamber  31  is formed therein. Therefore, less number of components needs to be fixed to the first housing  1  as compared with conventional cases. Therefore, it is relatively easy to maintain the cylinder chamber  31  in a hermetic state against the motor chamber  1   c . Furthermore, since this compressor comprises less number of components, it is possible to reduce the costs for machining, managing, and assembling individual components. 
     In this compressor, since the inside of the first housing  1  is partitioned by the cup member  7 , it is possible to dispose the suction pressure region at the position where the first housing  1  and the second housing  9  are joined together. Therefore, leakage of the refrigerating gas to the outside of the compressor is less likely to occur, and it is less necessary to provide a high-pressure seal such as a gasket. 
     Hence, this compressor is capable of realizing reduction in manufacturing costs. 
     Furthermore, in this compressor, since the cover member  11  is provided on the outer circumference of the cup member  7 , the discharge pressure space  37  of the cylinder forming portion  29  is able to communicate with the discharge chamber  9   a  in a state of being isolated from the motor chamber  1   c , i.e., the suction pressure region, due to the cover member  11 . Therefore, even when the cylindrical portion  1   d  of the first housing  1  may not be perfectly round, the motor chamber  1   c  in the first housing  1  is easily usable as the suction pressure region. 
     Furthermore, in this compressor, since the discharge pressure space  37  is closed by the cover member  11 , vibration and noise generated by the discharge reed valve  39  can be prevented from being transmitted outward. 
     Furthermore, in this compressor, the first housing  1  does not have a perfectly round shape due to the necessity for wiring, which is inherent in motor-driven compressors. In such a compressor, it is difficult to separate a discharge chamber from a motor chamber with a flat-plate wall, and it is also difficult to seal clearances so as to prevent leakage of refrigerating gas from around the wall. However, these difficulties can be easily overcome by employing the cup member  7  of the present invention. 
     Here, if it is attempted to cover a part of the outer circumference of the cup member  7  by the cover member  11  so as to partition the discharge pressure space  37 , a certain space in the radial direction will be needed for fastening bolts and the size of the compressor will be increased in the radial direction. In this respect, since the cover member  11  of this compressor is fastened to the cup member  7  with the bolts  60  extending in the axial direction, it is possible to arrange the bolts  60  such that the heads thereof are disposed in a space between the stator  15  of the motor mechanism  3  and the cup member  7 . Therefore, in this compressor, the suction pressure region and the discharge pressure region can be separated from each other without increasing the size of the compressor in the radial direction or the axial direction. 
     (Second Embodiment) 
     As shown in  FIG. 4 , a compressor according to the second embodiment employs a first housing  4  and a second housing  6 . The length of the first housing  4  in the axial direction is shorter than that of the first housing  1  in the first embodiment. The length of the second housing  6  in the axial direction is longer than that of the second housing  9  in the first embodiment. An O-ring  10  is provided between the first housing  4  and the second housing  6 . 
     A compression mechanism  12  is fitted into the second housing  6 . The compression mechanism  12  employs a cup member  8  formed into a cylindrical shape. The cup member  8  is fixed to the front face of the side plate  5  with plural bolts  25 . The cup member  8  includes a bottom portion  28  and a cylinder forming portion  30 . The bottom portion  28  is disposed closer to the motor chamber  1   c  than the cylindrical forming portion  30  and extends in the radial direction. An O-ring  34  is provided between the bottom portion  28  and the inner circumferential surface of the second housing  6 . The bottom portion  28  is provided with a shaft hole  28   a , through which the rotation shaft  19  is inserted. A discharge pressure space  37  is provided in a recessed manner in the cylinder forming portion  30  so as to open to the inside of the second housing  6 . The rotor  45 , the vanes  47   a  and  47   b , the cup member  8 , and the side plate  5  constitute the compression mechanism  12 . The other components are the same as those in the first embodiment. 
     Also in this compressor, by employing the cup member  8 , it is possible to exhibit the operational effects of the present invention except for those exhibited due to the cover member  11  in the first embodiment. Furthermore, since the cover member  11  in the first embodiment can be eliminated in this compressor, it is possible to realize further reduction in manufacturing costs. 
     Although the present invention has been described above by referring to the first and second embodiments, needless to say, the present invention is not limited to the first and second embodiments and may be modified as appropriate without departing from the gist of the invention. 
     For example, it is sufficient if the shaft holes  27   a  and  28   a  at the bottom portions  27  and  28  of the cup members  7  and  8  are configured so as to be able to maintain the hermetic state as much as possible with respect to the rotation shaft  19 . Furthermore, instead of plating the shaft holes  27   a ,  28   a  and  5   c , a slide bearing or a roller bearing may be provided between the rotation shaft  19  and the shaft holes  27   a ,  28   a  and  5   c.