Patent Publication Number: US-7722343-B2

Title: Sealed-type rotary compressor and refrigerating cycle device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2006-122483, filed Apr. 26, 2006, the entire contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a sealed-type rotary compressor and a refrigerating cycle device, and in particular, to a sealed-type rotary compressor and a refrigerating cycle device which can improve reliability by effectively feeding lubricant to a roller bearing provided at a rotary sliding portion with a rotary shaft. 
   2. Description of the Related Art 
   Conventionally, there is known a sealed-type rotary compressor with a roller bearing provided at the rotary sliding portion of, for example, between a main bearing and a main shaft portion of a rotary shaft, between a sub-shaft and a sub-baring portion of the rotary shaft, and between a roller which eccentrically rotates in a cylinder chamber of the compressor mechanism and a crank shaft portion of the rotary shaft (for example, see Jpn. Pat. Appln. KOKAI Publication Nos. 5-256283 and 2001-323886). By installing a roller bearing at the rotary sliding portion of the compressor, sliding resistance can be reduced and the coefficient of performance can be improved. 
   The above-mentioned sealed-type rotary compressor has had a following problem. That is, in order to improve the reliability of the rotary sliding portion, sufficient lubrication is required even for roller bearings but lubricant is not sufficiently fed to the roller bearing. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a sealed-type rotary compressor and a refrigerating cycle device which effectively feed lubricant to the roller bearing unit and can improve the reliability even when a roller bearing is provided to the rotary sliding portion. 
   To achieve the above object, the sealed-type rotary compressor and the refrigerating cycle device according to the present invention are configured as follows: 
   (1) A sealed-type rotary compressor is characterized by comprising: a sealed casing which stores lubricant on the bottom thereof; an electric motor unit which is housed in this sealed casing; a compression mechanism which is housed in the sealed casing, and has a cylinder that forms a cylinder chamber, a roller that eccentrically rotates in the cylinder chamber, and a vane that, makes reciprocating motion as the roller rotates; a rotary shaft which is pivotally supported by a main bearing and a sub-bearing and couples the electric motor unit and the compressor mechanism; a roller bearing provided in at least one position of between the main bearing and the rotary shaft, between the sub-bearing and the rotary shaft, and between the roller and the crank shaft unit of the rotary shaft; an oil filler opening which is provided to the rotary shaft along the center axis from one end face thereof and introduces lubricant on the bottom inside the sealed casing to the other end face side; and an oil filler opening, one end of which opens to the oil filler opening and the other end of which opens to the outer circumferential surface of the rotary shaft and opens towards the direction subject to a load when the roller bearing is subject to the large load, and which feeds lubricant to the roller bearing. 
   (2) A refrigerating cycle device is characterized by comprising the sealed-type rotary compressor, a condenser, an expansion device, and an evaporator. 
   According to the present invention, even when a roller bearing is provided to the rotary sliding unit, lubricant can be effectively fed to the roller bearing unit and the reliability can be improved. 
   Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
       FIG. 1  is a vertical cross-sectional view of a sealed-type rotary compressor according to a first embodiment of the present invention; 
       FIG. 2  is a cross-sectional view showing the positional relation between compression load and an oil filler opening in a roller bearing assembled in the sealed-type rotary compressor of the present invention; 
       FIG. 3  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing; 
       FIG. 4  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing; 
       FIG. 5  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing; 
       FIG. 6  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing assembled in the sealed-type rotary compressor; 
       FIG. 7  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing; 
       FIG. 8  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing; 
       FIG. 9  is a cross-sectional, view showing the positional relation between the compression load and the oil filler opening in the roller bearing; 
       FIG. 10  is a vertical cross-sectional view of a sealed-type rotary compressor according to a second embodiment of the present invention; 
       FIG. 11  is a vertical cross-sectional view of a sealed-type rotary compressor according to a third embodiment, of the present invention; 
       FIG. 12  is a cross-sectional view showing the positional relation between compression load and an oil filler opening in a roller bearing assembled in the sealed-type rotary compressor; 
       FIG. 13  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing 
       FIG. 14  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing; and 
       FIG. 15  is a cross-sectional view showing the positional relation between the compression load and the oil filler opening in the roller bearing. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a vertical cross-sectional view of a refrigerating cycle device  1  according to a first embodiment of the present invention and a sealed-type rotary compressor  10  which is assembled in refrigerating cycle device  1 ,  FIGS. 2 to 5  are cross-sectional views showing the positional relation between compression load and an oil filler opening in a roller bearing assembled in the sealed-type rotary compressor according to the present invention, and  FIGS. 6 to 9  are cross-sectional views showing the positional relation between the compression load and the oil filler opening in the roller bearing assembled in the sealed-type rotary compressor. 
   The refrigerating cycle device  1  is equipped with a condenser  2  that condenses refrigerant, an expansion device  3  connected to this condenser  2 , an evaporator  4  that is connected to this expansion device  3  and evaporates the refrigerant, and the sealed-type rotary compressor  10  connected to the outlet side of this evaporator  4 . 
   The sealed-type rotary compressor  10  is a single-type rolling-piston compressor and has a sealed casing  11 . In the sealed casing  11 , a rotary drive unit  20  provided on the upper side and a compression mechanism  30  provided on the lower side are housed, and the rotary drive unit  20  and the compression mechanism  30  are linked via a rotary shaft  50 . The sealed-type rotary compressor  10  is a vertically-provided type in which the rotary shaft  50  is provided along the vertical direction. 
   The rotary drive unit  20  has, for example, a brushless DC motor used, and is equipped with a stator  21  fixed into the inner surface of the sealed casing  11  and a rotor  22  which is arranged on the inner side of this stator  21  with a predetermined gap and fitted to the rotary shaft  50 . The rotary drive unit  20  is connected to an external power supply unit (not illustrated) to receive electric power supply. 
   The compression mechanism is equipped with a cylinder  31 , and a main bearing  32  and a sub-bearing  33  which grasp this cylinder  31  therebetween, and is screwed down with a bolt  35  together with a valve cover  34  provided on the main bearing side  32 . A discharge valve  36  is provided to the main bearing  32 . 
   The main bearing  32  and the sub-bearing  33  support the rotary shaft  50  by roller bearings  32   a ,  33   a , respectively. 
   A cylindrical extension unit  37  is provided to the main bearing  32 , and a roller bearing  38  is provided between the extension unit  37  and the rotary shaft  50 . A cylinder chamber  40  and a vane groove  41  (see  FIG. 2 ) which communicates with this cylinder chamber  40  are provided to the cylinder  31 . A vane  42  is housed in the vane groove  41  free to extrude and intrude with respect to the cylinder chamber  40 , and is energized toward the cylinder chamber  40  by a coil spring  43 . In the cylinder  31 , a roller  54  later discussed is eccentrically arranged, and by bringing the head end part of the vane  42  into contact with the outer circumferential surface of this roller  54 , the cylinder chamber is divided into a suction chamber V side and a compression chamber C side. 
   The rotary shaft  50  has a columnar shaft main body  51 , a crankshaft unit  52  provided at the position corresponding to the cylinder chamber  40  of the shaft main body  51 , and a roller  54  fitted to the outer circumference of this crankshaft unit  52  via a roller bearing  53 . 
   An oil filler opening  55  for feeding lubricant to roller bearings  32   a ,  33   a ,  38 , and  53  as well as seal units and the like are provided at the center of the rotary shaft  50 , and an impeller pump  56  for pumping up lubricant is inserted in the oil filler opening  55 . Oil filler openings  57   a  through  57   d  are provided from the oil filler opening  55  to the outer circumferential surface. The oil filler openings  57   a  through  57   d  have one end open to the oil filler opening  55  and the other end open to the outer circumference of the rotary shaft  50 . Consequently, the lubricant pumped up inside the oil filler opening  55  with rotation of the rotary shaft  50  is fed to each of the roller bearings  32   a ,  33   a ,  38 , and  53  by the oil filler openings  57   a  though  57   d.    
   In the refrigerating cycle device  1  configured in this way, the following operation takes place. That is, electric power is fed to the rotary drive unit  20 , the rotary shaft  50  is rotatably driven, and the compression mechanism  30  is driven. 
   In the compression mechanism  30 , the roller  54  makes eccentric rotation inside the cylinder chamber  40 . Because the vane  42  is constantly elastically pressure-energized by the coil spring  43 , the head end edge of the vane  42  slidably contacts with a circumferential wall of the roller  54  and divides the cylinder chamber  40  into the suction chamber V and the compression chamber C. When the inner circumferential surface rotary contact position of the roller  54  with the cylinder chamber  40  coincides with the vane groove  41  and the vane  42  is in the most retracted state, the space volume of this cylinder chamber  40  is maximized. The refrigerant gas is drawn into the cylinder chamber  40  and fills the chamber. 
   As the roller  54  eccentrically rotates, the rotary contact position of the roller  54  with respect to the inner circumferential surface of the cylinder chamber  40  moves and the volume of the compartmented compression chamber C in the cylinder chamber  40  decreases. That is, the refrigerant gas guided to the cylinder chamber  40  in advance is gradually compressed. The rotary shaft  50  is continuously rotated and the volume of the compression chamber C in the cylinder chamber  40  further decreases to compress the refrigerant gas, and when the pressure rises to a predetermined pressure, the discharge valve  36  opens. High-pressure gas is discharged into the sealed casing  11  via the valve cover  34  and fills the casing. Then, the high-pressure gas is discharged from the sealed casing  11 . 
   The high-pressure gas discharged from the sealed casing  11  is guided to the condenser  2 , condenses and liquefies, adiabatically expands by means of the expansion device  3 , deprives heat-exchanged air of evaporation latent heat at the evaporator  4  and exerts cooling effect. Then, the refrigerant after evaporated is drawn into the cylinder chamber  40  and circulates in the above-mentioned route. 
     FIGS. 2 to 5  are cross-sectional views showing positional relationship between the compression load and the oil filler opening  57   c  in the roller bearing  53  assembled in the sealed-type rotary compressor  10 . 
   In the sealed-type rotary compressor, in general, it is when the eccentric direction of the crankshaft unit  52  rotates about 180 degrees with the position on the vane  42  side used as the reference position (0 degrees) that the pressure of the compression chamber C reaches the discharge pressure, although this slightly differs depending on compressor operating conditions, etc. 
   Loads caused by a pressure difference between the pressure of the compression chamber C and the pressure of the suction chamber V are applied to the roller bearing  53 . That is, by the pressure difference, the roller  54  is pressed from the compression chamber C side to the suction chamber V side, and the force acts on the roller bearing  53 . 
   The force F caused by the differential pressure is expressed by:
 
 F=Pc·Ac−Ps·As   (1)
 
where Pc denotes pressure of the compression chamber C, Ac surface area of the roller  54  facing the compression chamber C, Ps pressure of the suction chamber V, and As surface area of the roller  54  facing the suction chamber V.
 
   It is when the pressure of the compression chamber C is the discharge pressure that the differential pressure is maximized, and it is when the eccentric direction of the crankshaft unit  52  rotates about 180 degrees from the reference position that the surface area of the roller  54  facing the compression chamber C is maximized while the pressure of the compression chamber C is the discharge pressure. Consequently, it is when the eccentric direction of the crankshaft unit  52  is located at the position 180 degrees from the reference position that the roller bearing  53  is subject to the greatest load ( FIG. 4 ), and the position is the portion facing the compression chamber C side as shown by the chain double-dashed line Q in  FIG. 4 , that is, within the range of about 210 to 330 degrees when the eccentric direction of the crankshaft unit  52  rotates 180 degrees from the reference position. 
   Consequently, forming the oil filler opening  57   c  at the position shown in  FIG. 2  makes it possible to feed lubricant at a proper timing and to a proper position. 
   Note that the outlet of the oil filler opening  57   c  is open on the upper side of the roller bearing  53 . Consequently, fresh lubricant can be fed more reliably to the portion subject to the largest load of the roller bearing  53  by gravity. 
     FIGS. 6 to 9  are cross-sectional views showing the positional relationship between the compression loads and the oil filler openings  57   a ,  57   b , and  57   d  at the roller bearings  32   a ,  33   a , and  38  assembled in the sealed-type rotary compressor  10 . 
   Loads caused by pressure difference between the pressure of the compression chamber C and the pressure of the suction chamber V are applied to the roller bearings  32   a ,  33   a , and  38 , as is the case with the roller bearing  53 . That is, by the pressure difference, the rotary shaft  50  is strongly pressed against the roller bearings  32   a ,  33   a , and  38 . The timing at which the roller bearings  32   a ,  33   a , and  38  are subject to the greatest loads is the same as that of the roller bearing  53 , but the position is the position deviated by 180 degrees from the case of the roller bearing  53 , that is, the range from about 30 to 150 degrees when the eccentric direction of the crankshaft unit  52  rotates 180 degrees from the reference position. 
   Consequently, forming the oil filler openings  57   a ,  57   b , and  57   d  at the positions shown in  FIG. 6  makes it possible to feed lubricant at a proper timing and to a proper position. 
   Note that the outlets of the oil filler openings  57   a ,  57   b , and bid are open on the upper side of the roller bearings  32   a ,  33   a , and  38 . Consequently, fresh lubricant can be fed more reliably to the portion subject to the largest load of the roller bearings  32   a ,  33   a , and  38  by gravity. 
   According to the sealed-type rotary compressor  10  configured in this way, fresh lubricant can be reliably fed to the portion of the roller bearing subject to the greatest load, and thus it is possible to provide a highly reliable compressor. 
     FIG. 10  is a vertical cross-sectional view showing a sealed-type rotary compressor  60  according to a second embodiment of the present invention. In  FIG. 10 , the same characters designate the same functional parts of  FIG. 1  and detailed description thereof will be omitted. 
   In the sealed-type rotary compressor  60 , a filter  61  is provided to the opening of the sub-bearing  33  facing the inlet of the oil filler opening  55  at the shaft center of the rotary shaft  50 . In addition, a permanent magnet  62  is mounted on the bottom surface of the sealed casing  11  and facing the opening of the sub-bearing  33 . 
   According to the sealed-type rotary compressor  60  configured in this way, by the filter  61  and the permanent magnet  62  provided, it is possible to prevent lubricant with abrasion powder and other iron-based foreign matters from being taken up to the oil filler opening  55  of the rotary shaft  50 , and still cleaner lubricant can be fed to each of the roller bearings  32   a ,  33   a ,  38 , and  53 . 
   Consequently, according to the sealed-type rotary compressor  60  according to the second embodiment, a highly reliable compressor can be provided. 
     FIG. 11  is a vertical cross-sectional view of a sealed-type rotary compressor  100  according to a third embodiment of the present invention, and  FIGS. 12 to 15  are cross-sectional views showing the positional relation between compression load and oil filler openings  171   a  through  171   h  in roller bearings  133   a ,  134   a ,  139 ,  164 , and  166  assembled in the sealed-type rotary compressor  100 . 
   The sealed-type rotary compressor  100  is a twin-type rolling-piston compressor and is equipped with a sealed casing  101 . In the sealed casing  101 , a rotary drive unit  120  provided on the upper side and a compression mechanism  130  provided on the lower side are housed, and the rotary drive unit  120  and the compression mechanism  130  are linked via a rotary shaft  160 . 
   The rotary drive unit  120  has, for example, a brushless DC motor used, and is equipped with a stator  121  fixed into the inner surface of the sealed casing  101  and a rotor  122  which is arranged on the inner side of this stator  121  with a predetermined gap and fitted to the rotary shaft  160 . The rotary drive unit  120  is connected to an external power supply unit (not illustrated) to receive electric power supply. 
   The compression mechanism  130  is equipped with a first cylinder  131  and a second cylinder  132 , and an intermediate partition board  139  held between these first cylinder  131  and the second cylinder  132 . The refrigerant is taken up from a suction passage  139   a  formed in the intermediate partition board  139  into the first cylinder  131  and the second cylinder  132 . 
   Furthermore, the first cylinder  131  and the second cylinder  132  are held between a main-bearing  133  and a sub-bearing  134  and is screwed down with a bolt  136  together with a valve cover  135  provided on the main bearing  133  side. 
   The main bearing  133  and the sub-bearing  134  support the rotary shaft  160  by roller bearings  133   a  and  134   a , respectively. A discharge valve  133   b  is provided to the main bearing  133 , and a discharge valve  134   b  is provided to the sub-bearing  134 . 
   A cylindrical extension unit  138  is provided to the main bearing  133 , and a roller bearing  139  is provided between the extension unit  138  and the rotary shaft  160 . A first cylinder chamber  140  and a vane groove  141  (see  FIG. 12 ) which communicates with this cylinder chamber  140  are provided to the first cylinder  131 . A vane (not illustrated) is housed in the vane groove  141  free to extrude and intrude with respect to the first cylinder chamber  140 , and is energized to the first cylinder chamber  140  side by a coil spring (not illustrated). A roller  165  later discussed is eccentrically arranged in the first cylinder  131 , and by bringing the head end part of the vane into contact with the outer circumferential surface of this roller  165 , the cylinder chamber is divided into a suction chamber V and a compression chamber C. 
   A second cylinder chamber  150  and a vane groove  151  (see  FIG. 12 ) which communicates with this second cylinder chamber  150  are provided to the second cylinder  132 . A vane (not illustrated) is housed in the vane groove  151  free to extrude and intrude with respect to the second cylinder chamber  150 , and is energized to the second cylinder chamber  150  side by a coil spring (not illustrated). A roller  167  later discussed is eccentrically arranged in the second cylinder  132 , and by bringing the head end part of the vane into contact with the outer circumferential surface of this roller  167 , the cylinder chamber is divided into a suction chamber V and a compression chamber C. 
   The rotary shaft  160  has a columnar shaft main body  161 , a first crankshaft unit  162  provided at the position corresponding to the first cylinder chamber  140  and a second crankshaft unit  163  provided at the position corresponding to the second cylinder chamber  150  of the shaft main body  161 . The eccentric directions of the first crankshaft unit  162  and the second crankshaft unit  163  differ by 180 degrees from each other. 
   The roller  165  is integrally formed via the roller bearing  164  on the outer circumference of the first crankshaft unit  162 , and the roller  167  is integrally formed via the roller bearing  166  on the outer circumference of the second crankshaft unit  163 . 
   Note that, in the present embodiment, the roller  165  and the outer race of the roller bearing  164  as well as the roller  167  and the outer race of the roller bearing  166  are integrally formed to achieve reduction of the number of components and the number of assembling man-hours as well as reduction of the compressor size, but as is the case with the sealed-type rotary compressor  10 , they may be formed separately. 
   An oil filler opening  170  for feeding lubricant to roller bearings  133   a ,  134   a ,  139 ,  164 , and  166  as well as seal units and the like is provided at the center of the rotary shaft  160 , and an impeller pump (not illustrated) for pumping up lubricant is inserted in the oil filler opening  170 . Oil filler openings  171   a  through  171   h  are provided from the oil filler opening  170  to the outer circumferential surface. The oil filler openings  171   a  through  171   h  have one end open to the oil filler opening  170  and the other end open to the outer circumference of the rotary shaft  160 . Consequently, the lubricant pumped up inside the oil filler opening  170  with rotation of the rotary shaft  160  is fed to each of the roller bearings  133   a ,  134   a ,  139 ,  164 , and  166  by the oil filler openings  171   a  though  171   n.    
   The sealed-type rotary compressor  100  according to the third embodiment is also rotatably driven in the same manner as the above-mentioned sealed-type rotary compressor  10  and the refrigerating cycle device  1  also functions in the same manner. 
   Next discussion will be made on the location in which the oil filler openings  171   a  through  171   h  are provided. It is preferable to install the outlets of the oil filler openings  171   a  through  171   h  to the vicinity of the portion in which the roller bearings  133   a ,  134   a ,  139 ,  164 , and  166  are subject to the greatest load, in the sealed-type rotary compressor  100  as well. In particular, there are two compressors in the twin type, and thus the rotary shaft  160  is subject to two load peaks in one rotation. 
   The location of the oil filler opening  171   e  which supplies lubricant to the roller bearing  164  and the location of the oil filler opening  171   f  which feeds lubricant to the roller bearing  166  are decided in accordance with the same principle as that shown in  FIGS. 2 to 5 . Because the eccentric directions of the first crankshaft unit  162  and the second crankshaft unit  163  differ by 180 degrees from each other, the locations of the oil filler opening  171   e  and the oil filler opening  171   f  differ by 180 degrees from each other. 
   On the other hand, because the eccentric directions of the first crankshaft unit  162  and the second crankshaft unit  163  differ by 180 degrees from each other, the roller bearings  133   a ,  134   a  and  139  have two timings in which the load increases. That is, when the oil filler openings are rotated by 180 degrees with the eccentric directions of the first crankshaft unit  162  and the second crankshaft unit  163  located in the vane direction, respectively, set as a reference, they must be located in the range of about 30 to 150 degrees. 
   Consequently, on the rotary shaft  160 , two each of oil filler openings  171   a ,  171   b ,  171   c ,  171   d ,  171   g , and  171   h  are provided corresponding to each of the roller bearings  133   a ,  134   a , and  139 . The oil filler openings  171   a ,  171   c , and  171   g  are provided at the same locations as those in  FIGS. 6 to 9 , while the oil filler openings  171   b ,  171   d , and  171   h  are provided at the locations 180-degree deviated from the oil filler openings  171   a ,  171   c , and  171   g , respectively. 
   According to the sealed-type rotary compressor  100  configured in this way, fresh lubricant can be reliably fed to the portion where the roller bearing is subject to the greatest load, and a highly reliable compressor can be provided. 
   Needless to say, the present invention is not be limited to the above-mentioned embodiments and various changes and modifications may be made in the invention without departing from the spirit and scope thereof. 
   Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.