Abstract:
A sleeve connecting a refrigerant pipe to a sealed compressor container has a reduced outer dimension and an inner step that accommodates the refrigerant pipe. An end of the refrigerant pipe abuts the inner step to accurately locate the refrigerant pipe to permit the refrigerant pipe to be secured in an desired relationship with the sleeve. The sleeve is attached to the container with increased accuracy and less chance of damage to the container through deformation during the attachment process. The sleeve and container may be composed of iron, while the refrigerant pipe may be composed of copper, so that the more rigid sleeve can accurately couple the less rigid refrigerant pipe to the container.

Description:
This application claims priority to a Japanese application Ser. No. 2004-284265 filed Sep. 29, 2004. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a compressor for compressing a refrigerant suitable for use in, for example, an air conditioning system, a water heater, a car air conditioner, a showcase, a freezer and refrigerator, or a refrigeration unit such as an automatic dispenser. 
   2. Description of the Related Art 
   In such a conventional compressor, for example, in a multistage compression type rotary compressor of an inside intermediate-pressure type, refrigerant gas is drawn into a low pressure chamber side of a cylinder from a refrigerant introduction pipe via a suction port of a first rotary compression element. The refrigerant gas is then compressed by operations of a roller and a vane to become intermediate pressure, and is discharged from a high pressure chamber side of the cylinder through a discharge port and a noise eliminating chamber into a sealed container. 
   The intermediate-pressure refrigerant gas in the sealed container is drawn into the lower pressure chamber side of the cylinder from a suction port of a second rotary compression element, and then is subjected to a second stage compression by the operations of the roller and the vane to become high-temperature and high-pressure refrigerant gas. The refrigerant gas flows from the high pressure chamber side of the cylinder through the discharge port and the noise eliminating chamber, and is discharged from a refrigerant discharge pipe to the outside of the compressor to be supplied to a refrigerating cycle, such as an air conditioning system, where the refrigerant gas radiates heat and is condensed to enter an evaporator. In the evaporator, heat of the refrigerant gas is absorbed and the refrigerant gas is evaporated. Thereafter the refrigerant gas is drawn again into the first rotary compression element through the refrigerant introduction pipe. This cycle is repeated. 
   In a sealed-type electric compressor with such an arrangement, a refrigerant introduction pipe or a refrigerant discharge pipe is connected to a cylindrical sleeve which is welded and fixed to a curved surface of a sealed container having a cylindrical shape. The typical conventional structure of the sleeve is shown in  FIGS. 6 and 7 . 
   A sleeve  141 X as exemplified in  FIG. 6  is made of iron material having large rigidity. A tapered tip end side of the sleeve  141 X is attached to an outer wall surface of the sealed container made of iron by projection welding with its inner surface brazed and fixed to a pipe member  145 X made of copper material having good ductility, but less rigidity than the iron, for connection with a refrigerant pipe. 
   A sealed pipe having its tip end leading to a cylinder of compression means existing in the sealed container is inserted into the inside of the pipe member  145 X made of copper. Into the sealed pipe, a refrigerant introduction pipe or a refrigerant discharge pipe is further fitted and connected. 
   The sleeve  141 X as exemplified in  FIG. 7  has a tapered side part with a large thickness, which is attached to the sealed container by the projection welding. 
   In a compressor including a sleeve having a shape such as that shown in  FIG. 6 , since a sleeve body incorporates therein the pipe, the sleeve body itself becomes larger than the pipe. This disadvantageously results in an increased diameter of a part which is projection welded, which leads to reduction in the strength of resistance to pressure of the welded part. The method for fixing the pipe involves simply inserting the copper pipe into the sleeve body and brazing it thereto, thus making it difficult to attach the pipe to the sleeve body at the right angle with respect to the body. This causes a problem that attachment of the refrigerant introduction pipe and the like cannot be carried out constantly in the same way. 
   In a compressor including a sleeve having a shape such as that shown in  FIG. 7 , since a part of a sleeve that is subjected to the projection welding has a large thickness, when the sleeve is attached to a container body by welding, the container body is largely pushed, thereby disadvantageously resulting in large deformation of the container body. 
   SUMMARY OF THE INVENTION 
   To solve the above problems, the invention has an object to provide a compressor which achieves downsizing of a sleeve to be attached to a sealed container, while improving the strength of resistance to pressure of a welded part, which can simply connect a copper pipe to a sleeve body made of iron at the right angle, and which prevents the sealed container from being largely pushed when the sleeve is attached to the sealed container by projection welding. 
   According to a first aspect of the invention, there is provided a compressor comprising sleeves respectively attached to an inlet and an outlet for a refrigerant provided in and opened to a sealed container, by projection welding, wherein a refrigerant is introduced from an outside of the container via a refrigerant introduction pipe connected to the container via the sleeve for the refrigerant inlet, and then the refrigerant introduced is compressed by compression means incorporated in the sealed container to be discharged to the outside of the container via a refrigerant discharge pipe connected to the container via the sleeve for the refrigerant outlet. The sleeve includes a through hole formed of a small-inner-diameter portion and a large-inner-diameter portion which are provided consecutively via a step portion. The sleeve is formed such that an outer peripheral part of the sleeve on an open end side of the small-inner-diameter portion is tapered. The sleeve is attached to the sealed container by the projection welding with the tapered part facing a side of the sealed container. 
   According to a second aspect of the invention, there is provided a compressor comprising sleeves respectively attached to an inlet and an outlet for a refrigerant provided in and opened to a sealed container, by projection welding, wherein a refrigerant is introduced from an outside of the container via a refrigerant introduction pipe connected to the container via the sleeve for the refrigerant inlet, and then the refrigerant introduced is compressed by compression means incorporated in the sealed container to be discharged to the outside of the container via a refrigerant discharge pipe connected to the container via the sleeve for the refrigerant outlet. The sleeve includes a through hole penetrating a small-outer-diameter portion and a large-outer-diameter portion which are provided consecutively via a step portion, an inner diameter of the through hole on an open end side of the small-outer-diameter portion being gradually increased towards the open end side of the small-outer-diameter portion. The sleeve is formed such that an outer peripheral part of the sleeve on the open end side of the small-outer-diameter portion is tapered. The sleeve is attached to the sealed container by the projection welding with the tapered part facing a side of the sealed container. 
   According to a third aspect of the invention, there is provided a compressor comprising sleeves respectively attached to an inlet and an outlet for a refrigerant provided in and opened to a sealed container, by projection welding, wherein a refrigerant is introduced from an outside of the container via a refrigerant introduction pipe connected to the container via the sleeve for the refrigerant inlet, and then the refrigerant introduced is compressed by compression means incorporated in the sealed container to be discharged to the outside of the container via a refrigerant discharge pipe connected to the container via the sleeve for the refrigerant outlet. The sleeve includes a through hole penetrating a small-outer-diameter portion and a large-outer-diameter portion which are provided consecutively via a step portion, the through hole being formed of a small-inner-diameter portion provided mainly in the small-outer-diameter portion and a large-inner-diameter portion provided in the large-outer-diameter portion, the small-inner-diameter portion and the large-inner-diameter portion being provided consecutively via another step portion, an inner diameter of the through hole on an open end side of the small-outer-diameter portion being gradually increased towards the open end side of the small-outer-diameter portion. The sleeve is formed such that an outer peripheral part of the sleeve on the open end side of the small-outer-diameter portion is tapered. The sleeve is attached to the sealed container by the projection welding with the tapered part facing a side of the sealed container. 
   In the compressor according to any one of the above-mentioned aspects, the sleeve made of iron-based material is provided with a pipe member made of copper-based material which member is inserted into the large-inner-diameter side of the through hole with an end thereof abutted against the step portion, and then is brazed and fixed to the sleeve. The sleeve is attached to the sealed container made of iron-based material by the projection welding. 
   In the first aspect, one end surface of the copper pipe or the like for connection with the refrigerant pipe is abutted against and fixed to the step portion provided in the sleeve, thereby facilitating positioning of the copper pipe in the sleeve at the right angle. Since the copper pipe does not penetrate to be set in the sleeve, the sleeve is downsized and the diameter of the part subjected to the projection welding becomes smaller, thereby improving the strength of resistance to pressure of the welded part. 
   In the second aspect, since the sleeve includes the tapered part with a small difference between the outer and inner diameters and is attached to the sealed container by the projection welding, the sealed container is not pushed and moved largely when pressure is applied in the projection welding. This leads to small deformation in the sealed container. Any fluctuations in stroke of pressure applied do not affect largely the size of the contact area with the sealed container. This results in small fluctuations in current density, and thus provides the stable welding. 
   In the third aspect, both effects of the first and second aspects can be produced. In the fourth aspect, the compressor of the invention can have enough strength of resistance to pressure to serve as a CO 2  compressor whose inner pressure may be high due to the use of CO 2  whose condensed temperature is high as the refrigerant. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic longitudinal sectional view showing one preferred embodiment of the invention (an inside intermediate-pressure type two-stage rotary compressor); 
       FIG. 2  is a longitudinal side view of a sleeve constituting a part of the compressor of the embodiment; 
       FIG. 3  is a longitudinal side view of a sealed container (through hole part) constituting a part of the compressor of the embodiment; 
       FIG. 4  is an enlarged longitudinal side view of a principal part of the compressor (through hole of the sealed container) of the embodiment; 
       FIG. 5  is a longitudinal side view of another sleeve constituting a part of the compressor of another embodiment; 
       FIG. 6  is a longitudinal side view of a sleeve constituting a part of a conventional compressor; and 
       FIG. 7  is a diagram explaining another sleeve constituting a part of a conventional compressor, and a container body to which the sleeve is attached. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In one preferred embodiment of the invention, there is provided a compressor which comprises sleeves respectively attached to an inlet and an outlet for a refrigerant which are provided in and opened to a sealed container, by projection welding, wherein a refrigerant is introduced from an outside of the container via a refrigerant introduction pipe connected to the container via the sleeve for the refrigerant inlet, and then the refrigerant introduced is compressed by compression means incorporated in the sealed container to be discharged to the outside of the container via a refrigerant discharge pipe connected to the container via the sleeve for the refrigerant outlet. The sleeve includes a through hole penetrating a small-outer-diameter portion and a large-outer-diameter portion which are provided consecutively via a step portion. The through hole is formed of a small-inner-diameter portion provided mainly in the small-outer-diameter portion and a large-inner-diameter portion provided in the large-outer-diameter portion, the small-inner-diameter portion and the large-inner-diameter portion being provided consecutively via another step portion. An inner diameter of the through hole on an open end side of the small-outer-diameter portion is gradually increased towards the open end side of the small-outer-diameter portion. The sleeve is formed such that an outer peripheral part of the sleeve on the open end side of the small-outer-diameter portion is tapered. The sleeve, which is made of iron-based material, is fitted into the large-inner-diameter side of the through hole with one end thereof abutted against the step portion, and is brazed and fixed to a pipe member made of copper-based material. The sleeve is attached to the sealed container by the projection welding with a tapered part facing a side of the sealed container made of iron-based material. 
   First Preferred Embodiment 
   A first preferred embodiment of the invention will be described below in detail with reference to  FIGS. 1 to 4 . 
     FIG. 1  is a longitudinal sectional view showing a multistage (two-stage) compression type rotary compressor of an inside high-pressure type  10  which includes first and second rotary compression elements  32  and  34  according to the first embodiment. For simple understanding, in  FIGS. 1 to 4 , elements that have the same functions as those explained in  FIGS. 6 and 7  are given the same reference numerals. 
   Referring to  FIG. 1 , the multistage (two-stage) compression type rotary compressor of the inside high-pressure type  10  is designed to compress a carbon dioxide (CO 2 ) which is to be used as a refrigerant for an air conditioning system. The rotary compressor  10  comprises a cylindrical sealed container  12  made of a steel plate, a drive element  14  disposed at and accommodated in an upper side of an inner space of the sealed container  12 , and a rotary compression mechanism  18  composed of the first rotary compression element  32  (first stage) and the second rotary compression element  34  (second stage) which are respectively disposed under the drive element  14  and driven by a rotary shaft  16  of the drive element  14 . 
   The sealed container  12  has its bottom serving as an oil reservoir, and includes a container body  12 A for accommodating therein the drive element  14  and the rotary compression mechanism  18 , and an end cap (cover)  12 B with a substantially bowl shape for closing an opening positioned at an upper part of the container body  12 A. A terminal  20  (wiring of which is omitted in description) for supplying power to the drive element  14  is attached to the center of the end cap  12 B. 
   The drive element  14  includes a stator  22  which is annularly attached to the inner peripheral surface of the sealed container  12  in the upper space thereof, and a rotor  24  inserted into and provided inside the stator  22  with a slight clearance. The rotary shaft  16  extending vertically through the center of the stator  22  is fixed to the rotor  24 . 
   The stator  22  includes a laminated body  26  formed by laminating doughnut-shaped electromagnetic steel plates and a stator coil  28  which is wound around the teeth of the laminated body  26  by direct winding (concentrating winding). The rotor  24  is formed by inserting a permanent magnet MG into a laminated body  30  made of electromagnetic steel plates like the stator  22 . 
   An intermediate partition plate  36  is held between the first rotary compression element  32  and the second rotary compression element  34 . That is, both the first rotary compression element  32  and the second rotary compression element  34  comprise the intermediate partition plate  36 , upper and lower cylinders  38 ,  40  disposed over and under the intermediate partition plate  36 , upper and lower eccentric portions  42 ,  44  provided on the rotary shaft  16 , upper and lower rollers  46 ,  48  which are eccentrically rotated inside the upper and lower cylinders  38 ,  40  while fitted into the upper and lower eccentric portions  42 ,  44  with a 180-degree phase difference therebetween, upper and lower vanes (not shown) abutting against the upper and lower rollers  46 ,  48  and partitioning each of the upper and lower cylinders  38 ,  40  into a lower pressure chamber side and a high pressure chamber side, and an upper support member  54  and a lower support member  56  serving both as supporting means by closing an upper opening face of the upper cylinder  38  and the lower opening face of the lower cylinder  40 , and as bearing means of the rotary shaft  16 . 
   There are provided in the upper support member  54  and lower support member  56 , suction passages  58 ,  60  which communicate with the inside of the upper and lower cylinders  38  and  40  through suction ports  161 ,  162 , and noise eliminating chambers  62 ,  64  which are recessed. Both the noise eliminating chambers  62 ,  64  have openings thereof opposite to the upper and lower cylinders  38 ,  40  closed with respective covers. That is, the noise eliminating chamber  62  is blocked by an upper cover  66 , and the noise eliminating chamber  64  is blocked by a lower cover  68 . 
   The upper cover  66  has its periphery fixed to the upper support member  54  from above by four main bolts  78 . The tip end of each of the main bolts  78  is screw-engaged with the lower support member  56 . Above the upper cover  66  is positioned the drive element  14 . 
   The noise eliminating chamber  62  of the upper support member  54  and the interior of the sealed container  12  communicate with each other through a discharge hole  120  which is open towards the drive element  14  in the sealed container  12 , penetrating the upper cover  66 . Thus, refrigerant gas compressed by the second rotary compression element  34  is discharged into the sealed container  12  through the discharge hole  120 . 
   The lower cover  68  is made of a doughnut-shaped circular steel plate, and it is fixed to the lower support member  56  from below by screwing four main bolts  129  at four spots on the periphery thereof to block an opening disposed on the lower surface of the noise eliminating chamber  64 . The tip end of each main bolt  129  is screw-engaged with the upper support member  54 . 
   Sleeves  141 ,  142 ,  143 , and  144  are respectively fixed to the side surface of the container body  12 A of the sealed container  12  by welding at open positions corresponding to the suction passages  58 ,  60  of the upper and lower support members  54 ,  56 , the noise eliminating chamber  64 , and the portion above the rotor  24  (portion directly above the drive element  14 ). 
   The sleeve  141  is vertically adjacent to the sleeve  142 . The sleeve  142  is positioned substantially opposite to the sleeve  143  with respect to the rotary shaft  16 . The sleeve  141  is displaced from the sleeve  144  by about 90 degrees with respect to the rotary shaft  16 . 
   One end of a refrigerant introduction pipe  92  is inserted into and connected to the sleeve  141  to communicate with the suction passage  58  of the upper support member  54 . The other end of the refrigerant introduction pipe  92  passes through the upper part of the sealed container  12 , and is inserted into and connected to the sleeve  143  to communicate with the noise eliminating chamber  64  of the lower support member  56 . A refrigerant introduction pipe  94  is inserted into and connected to the sleeve  142  to communicate with the suction passage  60  of the lower support member  56 . A refrigerant discharge pipe not shown is inserted into and connected to the sleeve  144 . 
   A method for attachment of the sleeves  141  to  144  will be explained below with reference to  FIGS. 2 and 3 . On the outer side, namely a curved surface  100  of the sealed container  12  (container body  12 A), circular through holes  102  are formed at positions (at four points in this case) to which the sleeves  141  to  144  are to be attached. A circular recess  104  is formed on the periphery of each of the through holes  102  on the outer surface side of the container body  12 A. Further, on the periphery of the through hole  102  located at the bottom of the recess  104 , is formed a flat surface  106  parallel to a tangent line with respect to an inner diameter of the container body  12 A of the sealed container  12 . 
   On the other hand, the sleeve  141  includes a small-outer-diameter portion  152  and a large-outer-diameter portion  153  which are provided consecutively via a surrounding step portion  151 . (Note that each of the sleeves  142  to  144  has the same structure as that of the sleeve  141 , and thus explanation thereof will be omitted.) On an open end side of the small-outer-diameter portion  152  opposite to the large-outer-diameter portion  153 , a tapered diameter-reduction portion  154  is provided which has its outer diameter gradually reduced towards the end. 
   The sleeve  141  includes a through hole  155  penetrating the small-outer-diameter portion  152  and the large-outer-diameter portion  153 . The through hole  155  is formed of a small-inner-diameter portion  155 A disposed mainly in the small-outer-diameter portion  152 , and a large-inner-diameter portion  155 C disposed in the large-outer-diameter portion  153 , the large-inner-diameter portion  155 C and the small-inner-diameter portion  155 A being provided consecutively via a surrounding step portion  155 B. On an open end side of the small-inner-diameter portion  155 A, a tapered diameter-enlargement portion  155   a  is provided which has its inner diameter gradually increased towards the end. 
   A pipe member  145  having good ductility, but less rigidity than the sealed container  12  is fitted into the large-inner-diameter portion  155 C of the through hole  155  with one end thereof abutted against the step portion  155 B. A surrounding recess  156  formed between the sleeve  141  and the pipe member  145  is filled with brazing filler metals such as a silver brazing filler metal, and then the pipe member  145  is fixed to the sleeve  141 , for example, by brazing in a furnace. 
   At this time, the pipe member  145  is inserted from the open end of the large-inner-diameter portion  155 C into the through hole  155 , and an end surface of the pipe member  145  is abutted against the surrounding step portion  155 B provided in the sleeve  141 , thereby facilitating positioning of the pipe member  145  in the sleeve  141  at the right angle. Note that the inner diameter of the small-inner-diameter portion  155 A of the through hole  155  is the same as that of the pipe member  145 . The outer circumferential surface of the pipe member  145  may be subjected to knurling treatment, thereby enhancing inflow properties of the brazing filler metal. 
   When the sleeve  141  with the pipe member  145  is attached to the container body  12 A, first the tapered diameter-reduction portion  154  of the sleeve  141  is fitted into the through hole  102  of the container body  12 A from the outside. At this time, the flat surface  106  is parallel to the tangential line of the outer side or curved surface  100  of the container body  12 A, and an axis  140  of the sleeve  141  is aligned with the through hole  102  so as to be perpendicular to the tangential line of the outer side or curved surface  100 . This causes the tapered diameter-reduction portion  154  of the sleeve  141  to abut against all corners between the flat surface  106  positioned at the bottom of the recess  104  and the through hole  102  in a circumferential direction. 
   Under this condition, projection welding is performed by applying pressure of about 0.4 MPa on the container body  12 A side via a flat end surface of the large-outer-diameter portion  153  using a jig for pressure application not shown, and by applying current of about 26 kA to a contact part between the diameter-reduction portion  154  of the sleeve  141  and the container body  12 A. This causes the abutment or contact part between the sleeve  141  and the container body  12 A to melt, so that the sleeve  141  is welded to the container body  12 A (see  FIG. 4 ). 
   It should be noted that technology for welding the sleeve  141  to the container body  12 A by the projection welding is well known, and hence a detailed explanation thereof will be omitted below. Since, in the embodiment of the invention described, the pipe member  145  does not penetrate to be set in the sleeve  141  of the rotary compressor  10 , the inner diameter of the tapered small-outer-diameter portion  152  side of the sleeve  141  can be thinner than that of the pipe member  145 , thereby downsizing the sleeve  141 , while improving the strength of resistance to pressure of the part subjected to the projection welding. 
   The tapered diameter-reduction portion  154  of the sleeve  141  is formed so as to have a diameter smaller than that of the large-outer-diameter portion  153  against which the jig for pressure application is abutted in the projection welding, and to have a smaller difference between the outer and inner diameters. A distance over which the container body  12 A is pushed and moved becomes so small that an amount of deformation of the container body  12 A can be decreased. 
   Further, since the difference between the outer and inner diameters of the diameter-reduction portion  154  is smaller than that of the conventional sleeve, any fluctuations in stroke of pressure applied in the projection welding does not affect largely the size of the contact area with the sealed container  12 A. This results in small fluctuations in current density, and thus provides the stable welding. 
   Since the diameter-enlargement portion  155   a  whose inner diameter is gradually increased towards the end of the sleeve  141  is provided in the through hole  155  of the sleeve  141 , even if the inner diameter of the small-inner-diameter portion  155 A side is decreased by heat and pressure applied in the projection welding, it does not become smaller than the inner diameters of other parts of the through hole  155 . Accordingly, the sealed pipe member  146  having good ductility is not inhibited from being fitted into the through hole  155  of the sleeve  141  for connection with the refrigerant introduction pipe  92  or the like. 
   The refrigerant introduction pipe  92  has its end inserted into and connected to the sleeve  141  attached to the sealed container  12  as described above to communicate with the suction passage  58  of the upper support member  54 . The other end of the refrigerant introduction pipe  92  passes through the upper part of the sealed container  12 , and is inserted into and connected to the sleeve  143  to communicate with the noise eliminating chamber  64  of the lower support member  56 . The refrigerant introduction pipe  94  is inserted into and connected to the sleeve  142  to communicate with the suction passage  60  of the lower support member  56 . The refrigerant discharge pipe not shown is inserted into and connected to the sleeve  144 . 
   In the rotary compressor  10 , carbon dioxide (CO 2 ) which is natural refrigerant is used as a refrigerant considering earth consciousness, inflammability, toxicity or the like, and an existing oil such as mineral oil, polyalkyleneglycol (PAG), alkylbenzene oil, ether oil, ester oil, or the like is used as the oil of the lubricant. 
   In the rotary compressor  10  of the embodiments with the above arrangement, when a stator coil  28  of the drive element  14  is energized via the terminal  20  and the wiring not shown, the drive element  14  is operated to rotate the rotor  24 . Once the rotor  24  is rotated, the upper and lower rollers  46 ,  48  engaged with the upper and lower eccentric portions  42 ,  44  which are integrally provided with the rotary shaft  16  are caused to rotate eccentrically in the upper and lower cylinders  38 ,  40 , as described above. 
   As a result, a lower pressure (about 4 MPaG) refrigerant gas supplied via a refrigerant introduction pipe  94  is drawn into the low pressure chamber side of the lower cylinder  40  from a suction port  162  via the suction passage  60  provided in the lower support member  56 . Then, the refrigerant gas is compressed by the operations of the roller  48  and the vane not shown of the first rotary compression element  32  to be changed into intermediate pressure (about 8 MPaG). Consequently, the intermediate pressure refrigerant gas is discharged into the noise eliminating chamber  64  from the high pressure chamber side of the cylinder  40  via the discharge port not shown. 
   The intermediate-pressure refrigerant discharged into the noise eliminating chamber  64  is drawn into the refrigerant introduction pipe  92 , passes over the suction passage  58  of the upper support member  54  via the outside of the sealed container  12 , and then is drawn into the low pressure chamber side of the upper cylinder  38  from the suction port  161 . At this time, the refrigerant gas is cooled when it passes through the refrigerant introduction pipe  92  provided outside the sealed container  12 . 
   The intermediate-pressure refrigerant gas drawn into the low pressure chamber side of the upper cylinder  38  is compressed by the operations of the roller  46  and the vane not shown of the second rotary compression element  34  into high-temperature and high-pressure (about 10 to 12 MPaG) refrigerant gas, which is then discharged from the high pressure chamber side of the cylinder  38  into the noise eliminating chamber  62  via the discharge port not shown. 
   The high-temperature and high-pressure refrigerant gas discharged into the noise eliminating chamber  62  is discharged from the discharge hole  120  of the upper cover  66  into an area under the drive element  14  inside the sealed container  12 , and then passes through a clearance between the members to reach the upper side of the drive element  14 , so that the refrigerant gas is discharged to the outside of the compressor via the sleeve  144 . 
   When the rotary compressor  10  is incorporated as, for example, a compressor for an air conditioner, the high-temperature and high-pressure refrigerant gas fed through the refrigerant discharge pipe connected to the sleeve  144  is introduced into a heat exchanger, so that the heat is radiated and the refrigerant gas is condensed. The condensed low-temperature and high-pressure refrigerant liquid is subjected to reduced pressure using an expansion valve to flow into an evaporator, where it is evaporated, and then flows back into the compressor through the refrigerant introduction pipe  94 . This cycle is repeated. The latent heat caused by evaporating the refrigerant in the evaporator produces the cooling effect. 
   The rotary compressor  10  may include a sleeve having a shape such as that shown in  FIG. 5  instead of a shape such as shown in  FIG. 2 , connected to the refrigerant introduction pipe  92  or the like and attached to the container body  12 A. 
   That is, the sleeve  141  as shown in  FIG. 5  may be a sleeve including the diameter-enlargement portion  155   a  without having the small-inner-diameter portion  155 A and the large-inner-diameter portion  155 C, and thus without having the surrounding step portion  155 B, with the through hole  155  having the constant inner diameter over the entire area except for the diameter-enlargement portion  155   a . (Note that each of the sleeves  142  to  144  has the same structure as that of the sleeve  141 , and thus explanation thereof is substituted for explanation of the sleeve  141 .) 
   In the sleeve  141 , a second surrounding step portion  151 A is provided on the side where the surrounding step portion  151  of the large-outer-diameter portion  153  is not provided, and a second small-outer-diameter portion  152 A is extended therefrom. The second small-outer-diameter portion  152 A has a diameter smaller than that of the small-outer-diameter portion  152 . 
   Even in the rotary compressor  10  with the sleeve  141  having a shape such as that shown in  FIG. 5 , attached to a main part of the container body  12 A by the projection welding, the difference between the outer and inner diameters of the tapered diameter-reduction portion  154  of the sleeve  141  is smaller than that of the conventional sleeve, resulting in a small length L over which the container body  12 A is pushed and moved in the projection welding, thereby reducing the amount of deformation of the container body  12 A. 
   Since the difference between the outer and inner diameters of the tapered diameter-reduction portion  154  of the sleeve  141  is set smaller, any fluctuations in stroke of pressure applied in the projection welding does not affect largely the size of the contact area with the sealed container  12 . This results in small fluctuations in current density, and thus provides the stable welding. 
   As the diameter-enlargement portion  155   a  whose inner diameter is gradually increased towards the end of the sleeve  141  is provided in the through hole  155  of the sleeve  141 , even if the inner diameter of the small-outer-diameter portion  152  on the end side is decreased by heat and pressure applied in the projection welding, it does not become smaller than the inner diameters of other parts of the through hole  155 . 
   Although in the first embodiment as described in detail, the multistage compression type rotary compressor of the inside high-pressure type is exemplified as the compressor of the invention, the invention is not limited thereto. The compressor of the invention may be a multistage compression type rotary compressor of an inside intermediate-pressure type, which has been proposed in patent publications or the like in the prior art. Note that in the invention, a one-stage compression type rotary compressor, or a one-stage or multistage compression type rotary compressor of a scroll type or a reciprocating type may be useful as compression means incorporated in the sealed container  12 .