JP4595943B2 - Compressor - Google Patents

Description

  The present invention relates to a compressor that compresses a low-pressure refrigerant to a high pressure in a compression mechanism section inside a sealed container.

  A conventional compressor includes an electric motor in a hermetic container, a low-stage compression mechanism unit driven by a rotary shaft connected to the electric motor, and a compression mechanism unit composed of a high-stage compression mechanism unit, and has a low pressure (suction pressure). Refrigerant is sucked into the low-stage compression mechanism from the low-stage suction pipe provided in the sealed container, where it is compressed to an intermediate pressure and discharged from the low-stage discharge pipe into the sealed container to create an intermediate pressure atmosphere in the sealed container. . The intermediate pressure refrigerant discharged from the low-stage compression mechanism into the sealed container is sucked into the high-stage compression mechanism from the high-stage suction pipe, and compressed to a high pressure (discharge pressure) there. It discharges to the refrigerant circuit outside.

  The high-pressure refrigerant compressed by the high-stage compression mechanism section is a small-capacity space formed in the high-stage compression mechanism section and sealed so as not to leak to the intermediate pressure in the sealed container. The high-stage compression mechanism that communicates with the compression chamber of the unit through the discharge valve is discharged from the high-stage compression chamber to the high-stage compression chamber without being opened in the sealed container. It is discharged outside the sealed container through the discharge pipe. This discharge silencing chamber is inside the airtight container of the compressor, and it is difficult in terms of compressor design to secure the volume necessary to perform the silencing function sufficiently, and the limited volume of the space is used as the discharge silencing chamber. Therefore, the discharge pulsation of the high-pressure refrigerant discharged from the high-stage compression mechanism cannot be sufficiently silenced, and the high-pressure refrigerant that is not sufficiently silenced is discharged from the compressor. Or vibration, or pulsation or compressor vibration propagates to the refrigerant circuit piping connected to the compressor, causing noise or vibration in the piping, or in some cases, fatigue failure due to repeated stress due to the vibration There was a problem.

  For this reason, a discharge muffler comprising a tank that is a volume part having a predetermined capacity to mute the pulsation of the discharged refrigerant is provided outside the compressor hermetic container, and the discharge muffler is held by a bracket fixed to the outer surface of the hermetic container, There is a compressor that is integrated with a hermetic container, connects a high-stage discharge pipe to the discharge muffler, silences pulsation by the discharge muffler, and then discharges the discharged refrigerant to the refrigerant circuit.

  The high-pressure refrigerant discharged from the high-stage compression mechanism section is discharged directly from the high-stage compression mechanism section through the high-stage discharge pipe to the piping of the refrigerant circuit outside the sealed container. The compressor refrigeration oil contained in the refrigerant to be discharged is discharged together with the high-pressure refrigerant into the refrigerant circuit outside the sealed container, and the refrigeration oil contained in the discharged refrigerant is returned to the compressor. If not, problems such as deterioration of the sliding characteristics and sealing performance of the compressor due to exhaustion of the refrigerating machine oil inside the compressor hermetic container, and hindrance to refrigerant circulation in the refrigerant circuit occur.

In order not to cause such a problem, there is an oil separator that separates the refrigeration oil contained in the high-pressure refrigerant discharged from the compressor from the refrigerant inside the volume part of a predetermined capacity and returns it to the compressor. Since the discharge muffler is composed of a tank having a volume part with a predetermined capacity, there is a discharge muffler that has this oil separation mechanism.

  An oil separator is provided in the form of a vertical partition that separates the internal space of the discharge muffler, which is a vertically long cylindrical tank that is fixed to the compressor sealed container via a bracket, and the discharge muffler is provided inside the discharge muffler. When the discharged refrigerant flowing into the inside from below passes through the oil separator, the refrigerating machine oil contained in the discharged refrigerant is separated from the refrigerant by adhering to the oil separator. The separated refrigerating machine oil flows down and is stored at the bottom of the discharge muffler tank, one through the tank bottom of the discharge muffler and the other through an oil return pipe that opens between the motor and the compression mechanism in the compressor hermetic container. Then, it flows into the compressor sealed container and returns to the oil sump at the bottom of the sealed container (see, for example, Patent Document 1).

JP-A-2004-239204 (Claim 1, FIG. 1, columns 0012 to 0044)

  Conventional compressors are equipped with a discharge muffler that is fixedly held in a sealed container and also has an oil separation mechanism. However, the oil separation mechanism is provided with an oil separation tool that divides the internal space of the volume part of the discharge muffler up and down. Therefore, the internal space of the discharge muffler volume part is divided, and the volume of each divided space is reduced. Therefore, the high-pressure discharge refrigerant discharged from the compression mechanism part by the discharge muffler. The pulsating component of the refrigerant cannot be silenced over a wide frequency range, and the pulsation of the discharged refrigerant cannot be sufficiently silenced.

In addition, the oil return pipe that discharges the refrigeration oil separated by the discharge muffler from the volume part of the discharge muffler and flows into the inside of the sealed container is opened between the motor inside the sealed container and the compression mechanism, so compression The refrigeration machine oil separated by the discharge muffler that returns to the oil reservoir in the machine closed container flows into the sealed container and then is discharged from the low-stage compression mechanism while returning to the oil reservoir at the bottom of the sealed container. The intermediate pressure refrigerant that satisfies the condition is drawn into the refrigerant flow when it flows out to the refrigerant outlet pipe to be sucked into the high stage compression mechanism section, and is taken out by the intermediate pressure refrigerant to the refrigerant outlet pipe to the high stage compression mechanism section. It is inhaled and cannot fully return to the oil sump. Finally, the oil in the oil sump in the sump is depleted, and the sliding characteristics and sealing performance of the compressor deteriorates. There is a problem of being locked and unable to drive It was.

  The present invention has been made to solve the above-described problems. The discharge muffler provided with the oil separation mechanism sufficiently silences the pulsation of the high-pressure discharged refrigerant discharged from the compression mechanism section, and is It is possible to obtain a compressor capable of separating the refrigerating machine oil contained in the discharged refrigerant from the refrigerant and reliably returning the separated refrigerating machine oil to the oil reservoir at the bottom of the sealed container.

In the compressor according to the present invention, an electric motor, is composed of a low-stage compression mechanism portion and the high-stage compression mechanism is driven by linked rotary shaft to the motor compressing and discharging low pressure refrigerant to a high pressure The compression mechanism is housed inside the sealed container, and a low-pressure refrigerant is compressed to an intermediate pressure by the low-stage compression mechanism and discharged to the inside of the sealed container. A compressor that compresses and discharges an internal intermediate-pressure refrigerant to a high pressure by a high- stage compression mechanism, and is supplied with a high-pressure discharge refrigerant that includes refrigeration oil discharged from the high- stage compression mechanism. A volume part that has a volume that silences the pulsation of the discharged refrigerant, and a high-pressure discharged refrigerant that blows along the inner surface of the volume part and supplies the high-pressure discharged refrigerant to the internal space of the volume part so as to make a swirl flow a tube, provided at the bottom of the volume An oil return pipe for discharging the refrigerating machine oil separated from the high-pressure refrigerant discharged by the internal space of the volume by the centrifugal force handed circumfluence from volume to outside of the volume, the discharge supply pipe of the high pressure within the volume open one on the bottom side of the volume than to position blown refrigerant, external to the other to open the refrigerating machine oil volume is discharged to the outside from the interior space of the volume of the refrigerant discharged from the high pressure separated discharge comprising a tube, a discharge muffler comprising a outside of the sealed container, the refrigerating machine oil discharged to the oil return pipe from the volume, and supplies to the compression chamber of the low-stage compression mechanism with low-pressure refrigerant, the oil from the volume A part of the refrigerating machine oil discharged to the return pipe is supplied to the compression chamber of the high stage compression mechanism together with the intermediate pressure refrigerant .

The compressor according to the present invention includes an electric motor, a low-stage compression mechanism section, and a high-stage compression mechanism section, and is driven by a rotating shaft connected to the motor to compress a low-pressure refrigerant to a high pressure. a compression mechanism portion for discharging, while housed inside of the sealed vessel, a low-pressure refrigerant in the low-stage compressing unit compresses the sealed container inside the discharge to an intermediate pressure, and the sealed container inside the intermediate pressure , a discharging that compressor and compressed to a high pressure Te the refrigerant in the sealed container inside the intermediate pressure to the high-stage compression mechanism, a high pressure discharge refrigerant containing refrigerating machine oil discharged from the high-stage compression mechanism section is supplied, a volume having an oil separating function of separating refrigeration oil from refrigerant discharged this pressure, a supply pipe for supplying the interior space of the volume of the high-pressure discharge refrigerant, provided in the bottom of the volume, volume It is separated from the high-pressure refrigerant discharged within the space of the product portion An oil return pipe for discharging to the outside of the volume of the refrigerating machine oil from the volume, and the discharge pipe refrigerating machine oil is discharged to the outside from the interior space of the volume of the refrigerant discharged from the high pressure separated, outside the sealed container provided, the refrigeration oil discharged to the oil return pipe from the volume product unit, the rewritable supplied with low-pressure refrigerant into the compression chamber of the low-stage compression mechanism, a part of the refrigerating machine oil discharged to the oil return pipe from the volume Are supplied to the compression chamber of the high-stage compression mechanism along with the intermediate-pressure refrigerant .

According to the present invention, the pulsating component of the at the inner space of the volume product portion, and the separation of refrigeration oil from the high pressure discharge refrigerant discharged from the high-stage compression mechanism, in the frequency domain have a wide discharge refrigerant in the high pressure it is the Mute, refrigerator separated from the high-pressure discharge refrigerant is supplied with low-pressure refrigerant into the compression chamber of the low-stage compression mechanism, the sliding of the sealing property and the low-stage compressor mechanism portion of the compression chamber A part of the refrigerator separated from the high-pressure discharged refrigerant is supplied to the compression chamber of the high-stage compression mechanism together with the intermediate-pressure refrigerant, and the sealability and high-stage compression of this compression chamber are improved. Since the lubricity of the sliding portion of the machine mechanism is improved, the effect of becoming a highly efficient and reliable compressor can be obtained .

According to the invention, the refrigerating machine oil separated from the high-pressure discharge refrigerant in the internal space of the volume portion and supplied to the compression chamber of the low-stage compression mechanism unit together with the low-pressure refrigerant is supplied from the low-stage compression mechanism unit to the intermediate pressure. is discharged into the sealed container part together with the refrigerant, since it returns to sump of the sealed container bottom and separated from the intermediate-pressure refrigerant in the sealed container interior without sump refrigerating machine oil is depleted, the oil sump of the refrigerating machine oil The effect of becoming a highly reliable compressor capable of maintaining an appropriate amount of oil storage is obtained .

Embodiment 1 FIG.
FIG. 1 is an explanatory longitudinal sectional view showing an internal intermediate pressure type two-stage compression compressor 1 according to Embodiment 1 for carrying out the present invention. The compressor 1 includes a two-stage compression type compression mechanism that includes a low-stage compression mechanism section 11 (hereinafter, low-stage section 11) and a high-stage compression mechanism section 12 (hereinafter, high-stage section 12) in an airtight container 10. And an electric motor 13 that rotationally drives the compression mechanisms 11 and 12 via the rotation shaft 14, and a discharge muffler 27 that is held on the outer surface of the sealed container 10. Two-stage compression type compression mechanism portions 11 and 12 are disposed below the electric motor 13, the low-stage portion 11 is disposed on the bottom side of the sealed container 10, and the high-stage portion 12 is disposed above the low-stage portion 11. Carbon dioxide is used as the refrigerant to be compressed.

  The sealed container 10 is hermetically sealed by joining an upper lid 10b and a bottom lid 10c to a cylindrical container 10a that is open at the top and bottom by welding or the like. The sealed container 10 may have a two-part configuration in which the top lid 10b is joined to a bottomed cylindrical container formed by drawing or the like. An oil sump 17 is provided at the bottom of the hermetic container 10 for storing refrigerating machine oil supplied to the compression mechanisms 11 and 12 and used for lubrication of the sliding parts and sealing of the compression chamber. Here, the refrigerating machine oil uses PAG (polyalkylene glycol) oil.

The electric motor 13 includes a stator 13a and a rotor 13b. In the outer periphery of the rotor 13b and the inner periphery of the stator 13a, a radial clearance called an air gap is provided substantially uniformly over the entire periphery. Although the stator 13a is not illustrated, a coil is wound in a concentrated winding manner on the inner teeth of substantially annular electromagnetic steel plates that are laminated and caulked and fixed, and the outer periphery of the laminated electromagnetic steel plates is enclosed by the sealed container 10. It is fixed to the inner circumference by shrink fitting. Since a plurality of cutouts are partially provided on the outer periphery of the electromagnetic steel plates on which the stator 13a is laminated, the upper and lower sides of the stator 13a are formed between the inner periphery of the hermetic container 10 and the outer periphery of the stator 13a by the cutouts. Is formed.

Although the rotor 13b is not shown in the figure, similarly to the stator 13a, annular electromagnetic steel plates are laminated and fixed by caulking, and permanent magnets such as rare earth magnets and ferrite magnets are embedded and laminated inside the electromagnetic steel plates. A plurality of air holes are provided as flow paths so as to communicate with the upper and lower sides of the magnetic steel sheet. In the rotor 13b, the inner periphery of the laminated electromagnetic steel sheets is shrink-fitted with the rotating shaft 14, and when electric power is supplied to the stator 13a, the rotating shaft 14 rotates integrally with the rotor 13b. Although not shown, a glass terminal is welded and fixed to the upper lid 10b of the sealed container 10, the glass terminal and the stator 13a are connected by lead wires, and electric power supplied from outside relays the glass terminal to the motor. 13.

Each of the low-stage part 11 and the high-stage part 12 includes a rotary compression mechanism that performs compression by reducing the volume of the compression chamber partitioned from the suction chamber by the vane while the roller rotates eccentrically in the cylinder. The compression chambers of the low step portion 11 and the high step portion 12 are separated by a partition plate arranged between the low step portion 11 and the high step portion 12. When electric power is supplied to the electric motor 13 and the rotary shaft 14 is rotationally driven by the electric motor 13, one is connected to the low-pressure pipe 50 of the refrigerant circuit using the compressor 1, and the other is connected to the low-stage section 11. A suction-pressure refrigerant (low-pressure refrigerant) is sucked into the lower stage portion 11 from the pipe 20. Then, the intermediate pressure is compressed from the low-stage discharge pipe 21 which is compressed to the intermediate pressure in the low-stage portion 11 and opens in the space A30 which is a space between the electric motor 13 and the high-stage portion 12 which is the compression mechanism portion in the sealed container 10. The entire amount of the refrigerant is discharged into the sealed container 10. Thereby, the inside of the sealed container 10 becomes an intermediate pressure atmosphere.

The intermediate-pressure refrigerant in the hermetic container 10 is temporarily sealed from the refrigerant outlet tube 22 that is installed on the wall of the hermetic container 10 facing the space A30 between the electric motor 13 and the high stage portion 12 and opens at one end inside the hermetic container 10. It is led out of the container 10. The intermediate-pressure refrigerant is connected to the refrigerant outlet pipe 22 at one end outside the sealed container 10 and the intermediate-pressure connecting pipe 25 connected to the high-stage suction pipe 23 at the other end and the high-stage suction pipe 23. Then, it is sucked into the high stage part 12, compressed to the discharge pressure (high pressure) at the high stage part 12, passes through the high stage discharge pipe 24 from the high stage part 12, and is discharged directly to the outside of the sealed container 10. The discharge refrigerant, which is a high-pressure refrigerant discharged from the high-stage discharge pipe 24, contains refrigeration oil supplied to the high-stage compression chamber.

The intermediate pressure connection pipe 25 is formed by bending a single pipe, but may be formed by connecting a plurality of pipes. Without the intermediate pressure connection pipe 25, either the refrigerant outlet pipe 22 or the high stage suction pipe 23 is formed long, or each of the refrigerant outlet pipe 22 and the high stage suction pipe 23 is formed long and directly cooled. The outlet pipe 22 and the high stage suction pipe 23 may be connected. The connection of the refrigerant outlet pipe 22 and the high stage suction pipe 23 includes the case of connecting via the intermediate pressure connection pipe 25 in the middle and the case of connecting both pipes 22 and 23 directly. Further, the refrigerant outlet pipe 22 and the intermediate pressure connecting pipe 25 may be collectively determined as a refrigerant outlet pipe, or the intermediate pressure connecting pipe 25 and the high stage suction pipe 23 may be collectively determined as a high stage suction pipe.

  Although not shown, the high stage portion 12 extends and closes the opening surface on the motor 13 side of the high stage cylinder that forms the high stage compression chamber on the inner periphery, and supports the rotary shaft 14 in the radial direction. A small-capacity space is formed between a frame including a bearing and a cover that covers a part of the upper surface of the frame and the upper surface of the frame. This space communicates with the high-stage compression chamber via the discharge valve. When the refrigerant is compressed to the discharge pressure in the high-stage compression chamber, the discharge refrigerant opens the discharge valve and is discharged into this space. In addition, a partition plate is in contact with the anti-motor 13 side (oil sump 17 side) of the high stage cylinder.

This space holds a seal material between the cover and the upper surface of the frame, and prevents the discharged refrigerant from leaking to the intermediate pressure inside the sealed container 10. Although the pulsation of the discharged refrigerant is partially relieved in this space, the pulsation is not sufficiently silenced due to the small capacity. A small-capacity space formed inside the hermetic container and discharged from the high-stage compression chamber is called a discharge silencer chamber. The other end of the high-stage discharge pipe 24 that opens to the outside of the sealed container 10 is opened in the discharge silencer chamber, and the discharged refrigerant is directly discharged from the high-stage portion 12 to the outside of the sealed container 10. . The discharge valve is installed on the frame.

  A bracket 26 is welded and fixed to the side surface of the sealed container 10, that is, the outer peripheral surface of the cylindrical container 10a in FIG. The bracket 26 is a holder for the discharge muffler 27, which is a feature of the present embodiment, and is a steel plate press-formed in a substantially U-shape. FIG. 2 is a top view of the main part of the compressor shown in FIG. 1, where the main part indicates the vicinity of the discharge muffler 27. As shown in FIG. 2, in the bracket 26, a curved surface portion 26a, which is a substantially U-shaped center, has a radius close to the radius of the outer peripheral surface of the cylindrical container 10a, and the curved surface portion 26a is connected to the outer peripheral surface of the cylindrical container 10a. It is welded and fixed to the side surface of the sealed container 10. The welding may be resistance welding, or the end of the curved surface portion 26a in the axial direction or the end in the horizontal direction may be arc-welded. The bracket 26 has a holding portion 26b on both sides in the horizontal direction continuously to the curved surface portion 26a. The holding portion 26b is opposite to the sealed container 10 from the curved surface portion 26a at a predetermined angle according to the outer diameter of the discharge muffler 27. It is bent in the direction of the side.

The discharge muffler 27 includes a volume portion 27a such as a vertically long cylindrical tank having a predetermined capacity. The volume portion 27a may be formed by welding lids on the upper and lower sides of the cylindrical container as in the case of the sealed container 10 or may be drawn. Alternatively, two cup-shaped containers having a bottom may be formed by overlapping the openings of each other and welding. By fixing the volume portion 27 a to the holding portion 26 b of the bracket 26 by welding, the discharge muffler 27 is fixedly held in the sealed container 10 of the compressor 1 and integrated with the compressor 1. Here, the volume 27a and the bracket holding part 26b are not fixed by welding, but the band is fixed to the holding parts 26b on both sides, and the volume part 27a is held between the band and the holding part 26b. The airtight container 10 of the compressor 1 may be fixed and held. When the band is fixed, a claw portion for hooking the band is provided on the holding portion 26b to fix the band to the bracket 26, or the extension portion is extended to the holding portion 26b to form a joint portion bent continuously from the holding portion 26b. The band is fixed to the bracket 26 with bolts at the joint.

  The discharge muffler 27 is provided with a supply pipe 27b and a discharge pipe 27c that extend on the upper surface of the volume part 27a and open one side and open the other side to the outside of the volume part 27a. One end of the supply pipe 27 b that opens to the outside of the volume portion 27 a is a high-pressure refrigerant that is discharged from the high-stage discharge pipe 24, one of which is connected to the other of the discharge pressure connection pipe 29 that is connected to the high-stage discharge pipe 24. The discharged refrigerant is blown out from the supply pipe 27b into the discharge muffler 27 (volume part 27a) through the discharge pressure connection pipe 29. The refrigerant compressed to the discharge pressure in the high stage portion 12 is discharged from the high stage discharge pipe 24 to the discharge muffler 27.

  The discharge pressure connecting pipe 29 is formed by bending a single pipe, but may be formed by connecting a plurality of pipes. Without passing through the discharge pressure connection pipe 29, either the high stage discharge pipe 24 or the supply pipe 27b is formed long, or each of the high stage discharge pipe 24 and the supply pipe 27b is formed long to directly perform the high stage discharge. You may connect the pipe | tube 24 and the supply pipe | tube 27b. The connection of the high-stage discharge pipe 24 and the supply pipe 27b includes a case where the high-pressure discharge pipe 24 and the supply pipe 27b are connected via the discharge pressure connection pipe 29 and a case where both the pipes 24 and 27b are directly connected. Further, the high-stage discharge pipe 24 and the discharge pressure connection pipe 29 may be collectively determined as a high-stage discharge pipe, or the discharge pressure connection pipe 29 and the supply pipe 27b may be collectively determined as a supply pipe.

As shown in FIG. 1, the supply pipe 27b penetrates the upper surface of the volume portion 27a in the axial direction, and the outer peripheral surface is brazed and fixed to the volume portion 27a, but the position close to the upper surface of the volume portion 27a inside the volume portion 27a. The end is bent by approximately 90 °, and one end inside the volume portion 27a of the supply pipe 27b opens in a substantially horizontal direction (a direction perpendicular to the axial direction of the volume portion 27a). Further, as shown in FIG. 2, the supply pipe 27b has an end that is a portion that bends and extends in the horizontal direction inside the volume 27a and extends in a direction substantially parallel to a tangent to the inner surface of the volume 27a that is circumferential. It is attached to be in a state. For this reason, the discharge refrigerant blown out from the supply pipe 27b to the volume portion 27a flows along the inner surface of the volume portion 27a as shown by the solid line arrow in FIG.

The supply pipe 27b may be attached in the horizontal direction through the side surface of the volume portion 27a without passing through the upper surface of the volume portion 27a. In that case, it is not necessary to bend supply pipe 27b inside volume 27a. Alternatively, the supply pipe 27b may be a straight pipe, and the end of the discharge pressure connection pipe 29 may be bent and connected to the supply pipe 27b which is a straight pipe. FIG. 3 is a schematic view showing the attachment direction of the supply pipe 27b when the supply pipe 27b is attached to the side surface of the volume portion 27a, and FIG. 3 (a) shows the supply pipe 27b extending inside. The supply pipe 27b is attached so that the end of the supply pipe 27b is substantially parallel to the tangential line of the inner surface of the volume part 27a, which is shifted from the center line of the volume part 27a, and opens in the horizontal direction. To do.

In the case where the supply pipe 27b is attached to the side surface of the volume part 27a, the discharged refrigerant can be supplied along the inner surface of the volume part 27a without allowing the supply pipe 27b to enter the volume part 27a, as shown in FIG. As shown in FIG. 3A, the supply pipe 27b may be attached in the same direction as in FIG. 3A, but the supply pipe 27b does not enter the volume 27a and opens in the horizontal direction facing the inner surface of the volume 27a.

In addition, if the discharge refrigerant | coolant discharged from the supply pipe | tube 27b flows along the inner surface of the volume part 27a, the direction and shape of the edge part of the supply pipe 27b inside the volume part 27a will be restricted to FIG.2 and FIG.3. is not. If the discharged refrigerant is to be supplied along the inner surface of the volume portion 27a, the direction of the end of the supply pipe 27b is not the radial direction of the volume portion 27a, but is inclined from the radial direction to the tangential side. It is best to be parallel to the tangential direction, but if an inclination angle is provided from the radial direction to the tangential direction, the discharged refrigerant supplied from the supply pipe 27b can flow along the inner surface of the volume 27a. it can. Further, the opening direction of the supply pipe 27b inside the volume portion 27a may be inclined from the horizontal direction as long as the discharged refrigerant is supplied along the inner surface of the volume portion 27a.

Similarly to the supply pipe 27b, the discharge pipe 27c penetrates the upper surface of the volume portion 27a in the axial direction, and the outer peripheral surface of the discharge muffler 27 is fixed to the volume portion 27a by brazing. In FIG. 2, the attachment positions of the supply pipe 27b and the discharge pipe 27c to the upper surface of the volume portion 27a are arranged on the same straight line passing through the center of the volume portion 27a, that is, the phase difference between both tubes 27b and 27c is 180 °. However, the present invention is not limited to this, and the phase of the attachment position of both the tubes 27b and 27c may be an angle other than 180 °. The discharge pipe 27c is bent at a plurality of locations (two locations in FIG. 1) inside the volume portion 27a, and is opened toward the bottom of the volume portion 27a in the axial direction at substantially the center of the volume portion 27a. The opening position in the axial direction inside the volume portion 27a of the discharge pipe 27c is set to be closer to the bottom side of the volume portion 27a than the opening position inside the volume portion 27a of the supply pipe 27b serving as the blowing position of the supply pipe 27b. The position is close to the bottom surface of 27a. Alternatively, the discharge pipe 27c may be formed as a straight pipe without being bent, and the straight pipe may be fixed to substantially the center of the upper surface of the volume portion 27a. The opening end outside the volume 27a of the discharge pipe 27c is connected to a high-pressure pipe 51 of a refrigerant circuit that uses the compressor 1.

The discharge muffler 27 includes an oil return pipe 27d installed at the bottom of the volume 27a. The oil return pipe 27 d is connected to the center of the bottom surface of the volume portion 27 a, and is installed so that one opens to the inside of the volume portion 27 a and the other opens to the inside of the sealed container 10 of the compressor 1. Both end portions of the oil return pipe 27d are fixed to the bottom surface of the volume portion 27a and the side surface of the sealed container 10 by brazing (cylindrical container 10a). The oil return pipe 27d may be formed by connecting a plurality of pipes. Here, the opening position of the oil return pipe 27d to the inside of the sealed container 10 is closer to the oil reservoir 17 side of the bottom of the sealed container 10 in the axial direction of the rotating shaft 14 than the opening position of the refrigerant outlet pipe 22 to the inside of the sealed container 10 ( It is installed so as to be downward) in FIG. The opening range of the refrigerant outlet pipe 22 into the sealed container 10 and the opening range of the oil return pipe 27d into the sealed container 10 are not overlapped with each other in the axial direction of the rotary shaft 14.

The phase of the opening position of the oil return pipe 27d into the sealed container 10 and the position of the opening position of the refrigerant outlet pipe 22 into the sealed container 10 are shifted. In FIG. 1, the phase difference between the two is set to be approximately 180 °. However, the present invention is not limited to this, and the opening range of the refrigerant outlet pipe 22 into the sealed container 10 and the oil return pipe 27d are not limited thereto. The opening range to the inside of the hermetic container 10 is installed so as not to overlap the rotation direction of the rotary shaft 14 at all.

In the compressor 1 holding such a discharge muffler 27, the discharge refrigerant, which is a high-pressure refrigerant including refrigeration oil discharged from the high-stage discharge pipe 24, is guided to the discharge muffler 27 through the discharge pressure connection pipe 29. . FIG. 4 is an explanatory diagram showing the flow of the discharge refrigerant inside the discharge muffler 27. The discharged refrigerant guided to the discharge muffler 27 is blown out from the supply pipe 27b into the volume portion 27a. At this time, in the state where the end of the bent supply pipe 27b having the open end in the horizontal direction on the upper surface side inside the volume 27a extends in a direction close to the tangential direction of the inner surface of the volume 27a that is circumferential. Therefore, the discharge refrigerant blown out from the supply pipe 27b to the volume part 27a swirls around the discharge pipe 27c along the inner surface of the volume part 27a as shown by the solid line arrow in FIG. Since the discharge pipe 27c is open to the bottom side from the discharge position of the discharge refrigerant in the supply pipe 27b inside the volume part 27a, the high-pressure discharge refrigerant that has turned into the swirl flow passes through the discharge pipe 27c. It descends toward the bottom side while turning in the internal space of the volume portion 27a to discharge to the outside. In order to lower the high pressure discharge refrigerant as a swirling flow in the internal space of the volume portion 27a toward the opening inside the volume portion 27a of the discharge pipe 27c while swirling toward the bottom side, the discharge refrigerant discharges from the supply pipe 27b. The opening which is the position may be inclined from the horizontal direction to the bottom side.

The high-pressure discharge refrigerant containing the refrigeration oil blown out from the supply pipe 27b into the volume 27a by the discharge muffler 27 descends as a swirling flow in the internal space of the volume 27a. Therefore, the density of the refrigeration oil becomes the density of the refrigerant. Since it is larger, the refrigerating machine oil contained in the discharged refrigerant is separated from the refrigerant by the swirling centrifugal force and adheres to the inner surface of the volume 27a. The attached refrigeration oil droplets are contacted with or combined with other refrigeration oil droplets, and flow down to the bottom of the volume portion 27a along the inner surface of the volume portion 27a by their own weight. Thus, the discharge muffler 27 has a swirling flow type oil separation function. Since the separated refrigerating machine oil gathers at the bottom of the volume 27a, the opening inside the volume 27a of the discharge pipe 27c is located close to the bottom, but the oil surface of the refrigerating machine oil gathered at the bottom of the volume 27a. Must be in a non-contact position.

The discharge refrigerant, which is a high-pressure refrigerant after the refrigerating machine oil is separated by the centrifugal force of the swirling flow, enters the discharge pipe 27c opened to the bottom of the volume portion 27a by releasing the swirling flow from the opening, The discharge pipe 27c is discharged to the outside, and since the discharge pipe 27c is connected to the high-pressure pipe 51 of the refrigerant circuit using the compressor 1, it is discharged to the high-pressure pipe 51. Since the volume portion 27a has a predetermined internal volume (capacity), and the oil separation tool or the like that partitions the internal space of the volume portion 27a up and down is not provided in the volume portion 27a, the predetermined internal volume Can be used almost as a muffler space. The reason for the almost total amount is that the volumes of the supply pipe 27b and the discharge pipe 27c that are extended inside the volume portion 27a are reduced.

Therefore, if the predetermined internal volume of the volume 27a that can be used as almost the entire amount of the muffler space is set to a volume that silences the pulsation of the discharged refrigerant, the sound can be completely silenced in the discharge muffler chamber of the high stage 12 within the volume 27a. The pulsation of the discharged refrigerant that has not occurred can be sufficiently silenced. In Patent Document 1, since an oil separator that partitions the inside of the tank, which is a volume portion, is installed, the internal space of the tank is divided by these oil separators, and the volume of each divided space is small. As a result, it becomes a multistage muffler that passes through a small volume of space substantially.

In the case of a small-capacity muffler, the low-frequency pulsation component is particularly difficult to mute, and the muffler effect of the pulsation component in a wide frequency range cannot be obtained. Even if the tank of Patent Document 1 has the same capacity (inner volume) as that of the volume part 27a of the present embodiment, for example, it is a multistage muffler that substantially owns a plurality of spaces having a capacity smaller than that capacity. The component is less likely to be silenced than the discharge muffler 27 of the present embodiment. Since the discharge muffler 27 of the present embodiment can use almost the entire inner volume of the volume portion 27a as one muffler space, it is a high-pressure refrigerant in a wide frequency range including a low frequency compared to Patent Document 1 of the same capacity. The pressure pulsation component of the discharged refrigerant can be silenced, and the pulsation of the discharged refrigerant can be sufficiently silenced. The silencing effect of the pulsation in the low frequency range, which was difficult to obtain in Patent Document 1, is obtained.

Further, the discharge muffler 27 sufficiently discharges the pulsation of the discharged refrigerant that is compressed and discharged by the high stage portion 12, and is combined with the noise reduction effect that reduces the vibration and noise of the compressor 1, and the discharge introduced into the external muffler 27. The refrigerant has a swirling flow type oil separation function in which the refrigerant is swirled in the internal space of the volume portion 27a and the refrigerating machine oil is separated from the discharged refrigerant. Further, since the discharge muffler 27 is fixedly held on the side surface of the hermetic container 10, it can save space and can be compressed as compared with a refrigerant circuit having a structure in which a muffler and an oil separator are installed as separate parts away from the main body of the compressor 1. Since the discharge muffler 27 is integrated with the machine 1, the degree of freedom in designing the refrigerant circuit is improved and the productivity is improved.

The inside of the volume portion 27a is at a high pressure (discharge pressure) due to the discharged refrigerant, and the inside of the sealed container 10 is filled with the intermediate pressure refrigerant discharged from the low-stage discharge pipe 21, and thus is separated inside the volume portion 27a. The refrigerating machine oil falling to the bottom of the volume 27a is discharged to the outside of the volume 27a through an oil return pipe 27d opened at the bottom of the volume 27a due to a pressure difference, as indicated by a dotted arrow in FIG. Since the other of the oil return pipe 27d (on the side opposite to the volume part 27a) is opened inside the sealed container 10, the refrigerating machine oil separated inside the volume part 27a passes through the oil return pipe 27d and is sealed in the compressor 1. It flows into the container 10 and returns to the oil sump 17 at the bottom of the sealed container 10.

Here, the opening of the oil return pipe 27d to the inside of the sealed container 10 is closer to the oil reservoir 17 (lower side in FIG. 1) than the opening position of the refrigerant outlet pipe 22 that guides the intermediate pressure refrigerant to the high stage portion 12 to the inside of the sealed container 10. ), The refrigerating machine oil that has flowed into the sealed container 10 from the oil return pipe 27d is caught in the flow of the intermediate pressure refrigerant flowing out of the space A30 in the sealed container 10 into the refrigerant outlet pipe 22, The refrigerant does not flow out into the refrigerant outlet pipe 22 together with the pressure refrigerant, and can be reliably returned to the oil sump 17. Therefore, the refrigerating machine oil in the oil sump 17 will not be depleted, and the amount of refrigerating machine oil stored in the oil sump 17 can be maintained at an appropriate amount. Avoided.

Further, since the method of oil separation in the discharge muffler 27 is to separate the refrigerating machine oil contained in the high-pressure discharge refrigerant using the centrifugal force of the swirling flow, the volume as disclosed in Patent Document 1 is used. Compared to so-called baffle plate oil separation, where the flow of discharged refrigerant is applied to an oil separator that divides the interior of the unit into upper and lower parts, there is no sudden drop in the flow rate of discharged refrigerant, and pressure loss of discharged refrigerant is reduced. Therefore, a reduction in compressor efficiency due to pressure loss can be avoided, and a highly efficient compressor can be obtained.

  In the discharge muffler 27, the opening end inside the volume portion 27a of the discharge pipe 27c is opened to the approximate center of the volume portion 27a, but the discharged refrigerant blown out to the volume portion 27a extends along the inner surface of the volume portion 27a. As long as a swirl flow can be generated, the center does not have to be the center, and the discharge pipe 27c may be installed as a straight pipe at a position eccentric from the center of the volume 27a. Further, the opening direction inside the volume portion 27a of the discharge pipe 27c may be inclined from the axial direction as long as it does not take in the swirling flow of discharged refrigerant.

  The discharge muffler 27 has an opening position of the oil return pipe 27d to the inside of the volume portion 27a substantially at the center of the volume portion 27a because the center portion is located most downward in the axial direction of the volume portion 27a. Yes, it is not limited to the central portion, but is provided in the vicinity of the lowermost portion of the bottom surface of the volume portion 27a. As a result, the refrigerating machine oil separated at the volume 27a and gathered at the bottom is prevented from remaining at the bottom of the volume 27a.

  The oil return pipe 27d communicates from the inside of the volume portion 27a, which is a high-pressure space, to the inside of the sealed container 10, which is an intermediate-pressure space. In order to reduce the pressure of a part of the discharged refrigerant, it is preferable to form it with a capillary tube or to interpose a pressure reducing valve in the middle.

  The compressor 1 is installed so that the phase of the opening position of the oil return pipe 27d into the sealed container 10 and the opening position of the refrigerant outlet pipe 22 into the sealed container 10 is approximately 180 °. These are maximally separated from each other in order to prevent the refrigerating machine oil from flowing out from the refrigerant outlet pipe 22 through the oil return pipe 27d. However, since the rotating shaft 14 is rotating inside the sealed container 10, there is a flow in the rotating direction. Therefore, in consideration of the flow of the intermediate pressure refrigerant in the closed container 10, in order to prevent the refrigerating machine oil from flowing out from the refrigerant outlet pipe 22 through the oil return pipe 27d, the oil return pipe 27d into the closed container 10 is prevented. The opening position does not overlap with the opening position of the refrigerant outlet tube 22 into the sealed container 10, and the position where the refrigerant outlet tube 22 opens into the sealed container 10 is advanced 180 ° in the rotation direction of the rotary shaft 14. It is good to install so that it is between.

  In the compressor 1 shown in FIG. 1, the low-stage discharge pipe 21 opens in the space A30 toward the electric motor 13 side, and the opening position of the electric motor 13 is also larger than the opening position of the oil return pipe 27d inside the sealed container 10. 1 (upper in FIG. 1), there is little risk of the refrigerating machine oil passing through the oil return pipe 27d being caught in the flow of the refrigerant discharged from the low stage discharge pipe 21, but the opening direction of the low stage discharge pipe 21 is horizontal. If the compressor is in the direction or the direction inclined from the axial direction, the refrigerating machine oil that has passed through the oil return pipe 27d is discharged to the intermediate pressure refrigerant discharged from the low-stage discharge pipe 21 into the sealed container 10. Installed so that the opening position of the oil return pipe 27d inside the sealed container 10 is closer to the oil reservoir 17 at the bottom of the sealed container 10 than the opening position of the low-stage discharge pipe 21 so as not to get caught in the flow of the intermediate pressure refrigerant. I have to .

  Even if the low-stage discharge pipe 21 opens toward the electric motor 13, the opening position of the low-stage discharge pipe 21 inside the sealed container 10 is higher than the opening position of the oil return pipe 27 d inside the sealed container 10. However, if it is close to the oil sump 17, depending on the phase difference between the two, the intermediate pressure refrigerant discharged from the low-stage discharge pipe 21 is entrapped in the refrigeration oil that has passed through the oil return pipe 27 d, and thus the sealed container 10 of the oil return pipe 27 d. The opening position to the inside must be installed closer to the oil sump 17 than the opening position of the low stage discharge pipe 21.

  In the compressor 1, the intermediate pressure refrigerant discharged from the low stage discharge pipe 21 includes refrigeration oil supplied to the low stage compression chamber of the low stage portion 11, and the intermediate pressure refrigerant is supplied to the refrigerant outlet pipe 22. Before reaching, it is necessary to separate the refrigerating machine oil inside the hermetic container 10 so that the refrigerating machine oil supplied to the high stage compression chamber of the high stage 12 is not excessive. Further, it is necessary to cool the electric motor 13 with the intermediate pressure refrigerant to prevent the motor efficiency from being lowered. Therefore, a phase difference is provided between the opening position of the low-stage discharge pipe 21 and the opening position of the refrigerant outlet pipe 22 into the sealed container 10, so that the intermediate pressure refrigerant discharged from the low-stage discharge pipe 21 flows into the closed container 10. It flows out to the refrigerant | coolant derivation | leading-out pipe | tube 22 almost without circulating, and is prevented from being supplied to the high stage part 12. FIG.

In the compressor 1, the opening position of the low-stage discharge pipe 21 (position for discharging intermediate pressure refrigerant into the sealed container 10) and the oil return pipe 27 d with respect to the opening position of the refrigerant outlet pipe 22 into the sealed container 10. The opening position to the inside of the sealed container 10 is set to a position where the phase is shifted by approximately 180 °.

  However, the opening positions of the three members are not limited to this, and the opening position of the oil return pipe 27d to the inside of the sealed container 10 is that the refrigerating machine oil flowing into the sealed container 10 through the oil return pipe 27d is a refrigerant. The refrigerant outlet pipe is positioned so as not to be taken out from the outlet pipe 22 and the opening position of the lower stage discharge pipe 21 is at a position where the intermediate pressure refrigerant discharged from the lower stage discharge pipe 21 can circulate inside the sealed container 10. What is necessary is just to install each with the predetermined | prescribed phase difference with respect to the opening position to 22 inside of the airtight container 10. FIG.

For example, the opening position of the oil return pipe 27d to the inside of the sealed container 10 is installed between the opening position of the refrigerant outlet pipe 22 to the inside of the sealed container 10 and a position advanced by 180 ° in the rotation direction of the rotary shaft 14, The opening position of the low-stage discharge pipe 21 is set so as to have a phase difference of approximately 180 ° from the opening position of the refrigerant outlet pipe 22 into the sealed container 10, and the phase difference between the three opening positions is approximately 120 respectively. It may be installed evenly at °.

  Since the compressor 1 is configured as described above, the compressor 1 is fixedly held in the sealed container 10, and the high-pressure discharged refrigerant is swirled in the internal space of the volume portion 27 a, and the refrigerating machine oil is converted from the discharged refrigerant by the centrifugal force of the swirling flow. The discharge muffler 27 separates the inner volume of the discharge muffler volume 27a without dividing it by an oil separator or the like that vertically divides the volume muffler space into one large muffler space. Refrigerating machine oil can be separated from the high-pressure discharged refrigerant discharged from the compression mechanism by force, and the pulsation component of the discharged refrigerant can be silenced in a wide frequency range, and the pulsation of the high-pressure discharged refrigerant can be sufficiently silenced.

In addition, the refrigerant oil separated from the discharged refrigerant in the volume part 27a of the discharge muffler and flowing into the sealed container 10 through the oil return pipe 27d flows into the refrigerant outlet pipe 22 inside the sealed container 10 and the intermediate pressure refrigerant flows. It is not caught in the flow, flows out of the refrigerant outlet pipe 22 and is not supplied to the high stage portion 12, and can be reliably returned to the oil reservoir 17 at the bottom of the sealed container 10. The risk of exhaustion can be avoided and the amount of refrigerating machine oil stored in the oil sump 17 can be maintained at an appropriate level. Further, when separating the oil in the discharge muffler 27, the centrifugal force of the swirling flow is used to separate the refrigerating machine oil from the discharged refrigerant, so that the pressure loss of the discharged refrigerant can be reduced and the discharge muffler is integrated with the compressor body. Thus, space saving can be achieved, and the effect of improving the degree of freedom and productivity of the refrigerant circuit design can be obtained.

In the compressor 1, the refrigerant outlet pipe 22 is provided, and after the intermediate pressure refrigerant inside the sealed container 10 is led out to the outside of the sealed container 10, one end passes through the high-stage suction pipe 23 positioned outside the sealed container 10. The high stage compression mechanism 12 is designed to be sucked, but the refrigerant outlet pipe 22 is not provided, the high stage suction pipe is accommodated in the sealed container 10, and one end of the high stage suction pipe is opened in the sealed container 10. However, there is also a compressor configured to connect the other end to the high-stage compression mechanism unit 12. In this case, the intermediate pressure refrigerant compressed by the low-stage compression mechanism 11 and discharged from the low-stage discharge pipe 21 to the inside of the sealed container 10 does not go out of the sealed container 10 and opens to the inside of the sealed container 10. It is sucked into the high stage compression mechanism 12 from the stage suction pipe.

In the internal circulation type internal intermediate pressure type two-stage compression compressor in which the high-stage suction pipe as described above is accommodated in the closed container 10, the opening of the oil return pipe 27d into the closed container 10 is an intermediate pressure refrigerant. By placing the high-stage suction pipe for sucking the high-stage portion 12 inside the closed container 10, that is, the position of the intermediate pressure refrigerant suction port of the high-stage suction pipe, closer to the oil reservoir 17, the oil return pipe The refrigerating machine oil that has flowed into the sealed container 10 from 27d is prevented from flowing into the high-stage suction pipe housed in the sealed container 10 together with the intermediate pressure refrigerant in the sealed container 10 to ensure the oil reservoir 17 Can be returned to.

Further, in the internal circulation type internal intermediate pressure type two-stage compression compressor as described above, the circumferential arrangement (phase difference) of the oil return pipe 27d, the low-stage discharge pipe 21, and the high-stage suction pipe is as follows. The opening position of the refrigerant outlet pipe 22 of the compressor 1 into the sealed container 10 can be replaced with the opening position (intermediate pressure refrigerant suction port) of the high-stage suction pipe stored in the sealed container 10. A similar effect can be obtained.

Embodiment 2. FIG.
FIG. 5 is an explanatory longitudinal sectional view showing an internal intermediate pressure type two-stage compression compressor 2 according to Embodiment 2 for carrying out the present invention. 5 that are the same as those in FIG. 1 are the same or similar parts as the compressor 1 in FIG. 1, and a description thereof is omitted here. The compressor 2 shown in FIG. 5 is different from the compressor 1 shown in FIG. 1 in that the opening position of the oil return pipe 27 e into the sealed container 10 faces the oil sump 17. An oil return pipe 27 e is opened in the refrigerating machine oil stored in the oil sump 17. The refrigerating machine oil separated from the discharged refrigerant by the discharge muffler 27 is directly returned to the refrigerating machine oil in the oil sump 17.

Therefore, the refrigerating machine oil exists in a region on the oil sump 17 side of the oil return pipe 27e up to a height that is pressure-balanced with the oil level height of the refrigerating machine oil in the oil sump 17 inside the closed container 10. Similar to the compressor 1, the oil return pipe 27e may be formed by connecting a plurality of pipes and communicates from the high pressure space to the intermediate pressure space. Is not present inside the volume 27a, it is preferable to form a part of the discharged refrigerant by a capillary tube or to interpose a pressure reducing valve in the middle in order to reduce the pressure of the discharged refrigerant to an intermediate pressure.

In the compressor 2, the refrigeration oil separated from the discharge refrigerant by the discharge muffler 27 can be returned directly from the oil return pipe 27 e to the refrigeration oil in the oil sump 17, so that the flow of the intermediate pressure refrigerant in the sealed container 10 can be reduced. Not affected.

Therefore, the refrigerating machine oil passing through the oil return pipe 27e is intermediate regardless of the position (phase difference) of the oil return pipe 27e into the closed container 10 with respect to the opening position of the refrigerant outlet pipe 22 into the closed container 10. Since it is possible to avoid being taken out to the refrigerant outlet pipe 22 by the pressurized refrigerant, in addition to the effects of the first embodiment, the degree of freedom in designing the arrangement of the oil return pipe 27e and the refrigerant outlet pipe 22 in the circumferential direction of the sealed container 10 is increased. The effect which can improve the workability | operativity regarding the connection to the airtight container 10 of the oil return pipe | tube 27e can be acquired.

In the compressor 2 as well, the configurations of the supply pipe 27b, the discharge pipe 27c, the intermediate pressure connection pipe 25, the discharge pressure connection pipe 29, the bracket 26, etc. of the discharge muffler 27 are the same as those in the first embodiment. In the internal space of the volume portion 27a, similarly to the compressor 1, the discharged refrigerant is used as a swirling flow, and the refrigerating machine oil is separated from the discharged refrigerant using the centrifugal force of the swirling flow. It is returned to the oil sump 17 by the pressure difference from the return pipe 27e. The relationship between the opening positions of the intermediate pressure outlet pipe 22 and the low-stage discharge pipe 21 inside the sealed container 10 is the same as that of the first embodiment.

The compressor 2 includes a refrigerant outlet pipe 22, and after the intermediate pressure refrigerant inside the sealed container 10 is led out to the outside of the sealed container 10, one end thereof passes through a high-stage suction pipe 23 positioned at the outside of the sealed container 10. The high stage compression mechanism 12 is designed to be sucked, but the refrigerant outlet pipe 22 is not provided, the high stage suction pipe is accommodated in the sealed container 10, and one end of the high stage suction pipe is opened in the sealed container 10. However, the same effect can be obtained by applying to an internal circulation type internal intermediate pressure type two-stage compression compressor configured to connect the other end to the high-stage compression mechanism section 12.

Embodiment 3 FIG.
FIG. 6 is an explanatory longitudinal sectional view showing an internal intermediate pressure type two-stage compression compressor 3 according to Embodiment 3 for carrying out the present invention. 6 that are the same as those in FIGS. 1 and 5 are the same as or similar to those in the compressor 1 in FIG. 1 and the compressor 2 in FIG. 5, and a description thereof is omitted here. The compressor 3 shown in FIG. 6 is different from the compressor 1 shown in FIG. 1 or the compressor 2 shown in FIG. 5 in that the opening end of the oil return pipe 27f on the side opposite to the volume 27a side is inside the sealed container 10. It is a point that it opens to the low stage suction pipe 20 instead of opening. One of the oil return pipes 27f communicates with the inside of the volume portion 27a, and the other (on the opposite volume portion 27a side) communicates with the suction pressure (low pressure) space.

For this reason, one of the refrigerating machine oil separated from the discharge refrigerant inside the volume 27a passes through the oil return pipe 27f communicating with the suction pressure space by the discharge pressure (high pressure) in the volume 27a due to the pressure difference. The low-pressure refrigerant flows into the low-pressure suction pipe 20 which is the suction pressure space and flows through the low-pressure suction pipe 20 and is supplied from the low-pressure suction chamber of the low-pressure section 11 to the low-pressure compression chamber. This contributes to the lubrication of the seal and the sliding portion of the low step portion 11. The refrigerating machine oil separated from the discharge refrigerant by the discharge muffler 27 is not fed into the sealed container 10 and returned to the oil sump 17 but is supplied in its entirety to the low-stage compression chamber of the low-stage portion 11.

The refrigerating machine oil that has passed through the oil return pipe 27f supplied to the low-stage compression chamber is discharged from the low-stage discharge pipe 21 into the space A30 together with the intermediate-pressure refrigerant compressed there, and the intermediate-pressure refrigerant is Before flowing out to the refrigerant outlet pipe 22, the refrigerant is separated from the intermediate pressure refrigerant inside the sealed container 10 and returned to the oil sump 17. In this compressor 3, the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 returns to the oil sump 17 through the low stage portion 11 from the oil return pipe 27f. In the compressor 1 and the compressor 2, the refrigeration oil separated from the refrigerant discharged by the discharge muffler 27 is returned to the oil reservoir 17, and the refrigeration oil is supplied from the oil reservoir 17 to the lower stage portion 11. 3, the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 is supplied to the low-stage compression chamber of the low-stage portion 11 before returning to the oil sump 17.

Here, the oil return pipe 27f may be formed by connecting a plurality of pipes and communicates from the high-pressure space to the low-pressure space. If not, a part of the discharged refrigerant is depressurized to a low pressure, so it is preferable to form it with a capillary tube or to interpose a depressurization valve in the middle.

The compressor 3 supplies the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 to the low-stage compression chamber of the low-stage portion 11 together with the low-pressure refrigerant via the oil return pipe 27f and the low-stage suction pipe 20. The sealing property of the compression chamber is improved, and the effect of becoming a highly efficient compressor is obtained. The compressor 3 uses carbon dioxide, the operating pressure is extremely high, the pressure in the low-stage compression chamber, the suction pressure, and the differential pressure are large, preventing leakage from the low-stage compression chamber and preventing an increase in leakage loss. Therefore, since a higher sealing effect is required compared to a compressor using a refrigerant such as a conventional HFC refrigerant, the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 is transferred to the low stage compression chamber of the low stage 11. Supplying contributes to improving the sealing performance of the low-stage compression chamber. Moreover, the effect of becoming a highly reliable compressor is acquired by the lubricity improvement of the sliding part of the low step part 11. FIG.

Further, the pulsation of the refrigerant discharged from the high stage portion 12 can be sufficiently silenced by the discharge muffler 27, and the refrigerating machine oil separated from the refrigerant discharged by the oil separation mechanism is discharged from the low stage portion 11 into the sealed container 10. Since the oil is separated in the sealed container 10, it can be returned to the oil reservoir 17 at the bottom of the sealed container 10, avoiding the risk of exhausting the refrigerating machine oil in the oil reservoir 17, and reducing the amount of refrigerating machine oil stored in the oil reservoir 17. An appropriate amount can be maintained.

Further, similar to the compressor 1, when separating the oil in the discharge muffler 27, the centrifugal oil of the swirling flow is used to separate the refrigerating machine oil from the discharged refrigerant, so that the pressure loss of the discharged refrigerant can be reduced, and the discharge muffler Space saving can be achieved by integrating with the compressor body, and the effect of improving the degree of freedom and productivity of designing the refrigerant circuit can be obtained.

In the compressor 3, the connection of the oil return pipe 27f to the suction pressure space is configured to be connected to the low-stage suction pipe 20. However, the other side of the oil return pipe 27f (on the opposite volume portion 27a side) is connected to the low pressure of the refrigerant circuit. A similar effect can be obtained by connecting to the pipe 50 so as to open, or connecting through the sealed container 10 so as to open to the suction pressure space of the low stage portion 11 such as the low stage suction chamber. .

In the compressor 3 as well, the configurations of the supply pipe 27b, the discharge pipe 27c, the intermediate pressure connection pipe 25, the discharge pressure connection pipe 29, the bracket 26, and the like of the discharge muffler 27 are the same as those in the first embodiment. In the internal space of the volume portion 27a, as in the compressor 1, the discharged refrigerant is used as a swirling flow, and the refrigerating machine oil is separated from the discharged refrigerant using the centrifugal force of the swirling flow. The relationship between the opening positions of the intermediate pressure outlet pipe 22 and the low-stage discharge pipe 21 inside the sealed container 10 is the same as that of the first embodiment.

The compressor 3 includes a refrigerant outlet pipe 22, and after the intermediate pressure refrigerant inside the sealed container 10 is led out to the outside of the sealed container 10, one end thereof passes through a high-stage suction pipe 23 positioned at the outside of the sealed container 10. The high stage compression mechanism 12 is designed to be sucked in, but the refrigerant outlet pipe 22 is not provided, the high stage suction pipe is accommodated in the sealed container 10, and one end of the high stage suction pipe is opened in the sealed container 10. However, the same effect can be obtained by applying to an internal circulation type internal intermediate pressure type two-stage compression compressor configured to connect the other end to the high-stage compression mechanism section 12.

Embodiment 4 FIG.
FIG. 7 is an explanatory longitudinal sectional view showing an internal intermediate pressure type two-stage compression compressor 4 according to Embodiment 4 for carrying out the present invention. 7, the same reference numerals as those in FIGS. 1, 5, and 6 are the same or similar parts as the compressor 1 in FIG. 1, the compressor 2 in FIG. 5, and the compressor 3 in FIG. 6. The description here is omitted. The compressor 4 shown in FIG. 7 differs from the compressor 1 shown in FIG. 1, the compressor 2 shown in FIG. 5 and the compressor 3 shown in FIG. 6 in that two oil return pipes are provided, and one oil return pipe 27g Similar to the compressor 3 of FIG. 5, the opening end on the opposite side to the volume portion 27a side is opened to the low-stage suction pipe 20, and the other oil return pipe 27h is opened on the opposite side to the volume portion 27a side. The end is open to the high-stage suction pipe 23. One of the oil return pipes 27g communicates with the inside of the volume part 27a, the other (reverse volume part 27a side) communicates with the suction pressure (low pressure) space, and one of the oil return pipes 27h enters the interior of the volume part 27a and the other (anti-volume part 27a side) communicates with the suction space of the high step portion 12.

The oil return pipe 27g can be connected to the suction pressure space by connecting the other side of the oil return pipe 27f (on the opposite volume 27a side) to the low-pressure pipe 50 of the refrigerant circuit or through the sealed container 10. Then, it may be connected so as to open to a suction pressure space such as a low-stage suction chamber of the low-stage portion 11. Further, the communication of the oil return pipe 27h to the suction space of the high stage portion 12 is performed by connecting the other side (the opposite volume portion 27a side) of the oil return pipe 27h to the intermediate pressure connection pipe 25 or the refrigerant outlet pipe 22. Alternatively, it may be connected so as to pass through the sealed container 10 and open to an intermediate pressure space such as a high stage suction chamber of the high stage 12. The other of the oil return pipe 27h (on the opposite volume part 27a side) is connected to the suction space of the high stage part 12 from the refrigerant outlet pipe 22 through the high stage suction pipe 23 to the high stage suction chamber of the high stage part 12. is there. Hereinafter, the oil return pipe 27g communicating with the low pressure space is referred to as a low stage oil return pipe 27g, and the oil return pipe 27h communicating with the suction space of the high stage portion 12 is referred to as a high stage oil return pipe 27h.

In the compressor 4, the refrigerating machine oil separated from the refrigerant discharged inside the volume portion 27 a is one of the discharge pressure (high pressure) in the volume portion 27 a and the other is pressured through the low-stage oil return pipe 27 g communicating with the suction pressure space. Passing through the difference and flowing into the low-stage suction pipe 20 which is the suction pressure space, one is the discharge pressure (high pressure) in the volume portion 27a, and the other is the intermediate pressure that becomes the suction space of the high-stage portion 12 The high pressure oil return pipe 27h communicated with the space passes through the high pressure oil pressure pipe 27h and flows into the high pressure suction pipe 23.

The two oil return pipes 27g and 27h have different pressure differences at the inlet and outlet, and the volume of the refrigerating machine oil that passes through the low-stage oil return pipe 27g having a large pressure difference is larger than that of the refrigerating machine oil that passes through the high-stage oil return pipe 27h. More than the volume. The refrigerating machine oil that has flowed into the low-stage suction pipe 20 through the low-stage oil return pipe 27g is supplied to the low-stage compression chamber of the low-stage portion 11 together with the low-pressure refrigerant flowing through the low-stage suction pipe 20. This contributes to the lubrication of the seal and the sliding portion of the low step portion 11. Then, the intermediate pressure refrigerant compressed in the low stage portion 11 from the low stage compression chamber is discharged into the space A30 from the low stage discharge pipe 21, and before the intermediate pressure refrigerant flows into the refrigerant outlet pipe 22, The refrigerant is separated from the intermediate pressure refrigerant and returned to the oil sump 17.

On the other hand, the refrigerating machine oil that has flowed into the high-stage intake pipe 23 through the high-stage oil return pipe 27h is supplied to the high-stage compression chamber of the high-stage portion 12 together with the intermediate pressure refrigerant flowing through the high-stage intake pipe 23. This contributes to lubrication of the seal of the stage compression chamber and the sliding part of the high stage part 12. Then, together with the discharge refrigerant compressed in the high stage portion 12 from the high stage compression chamber, it reaches the discharge muffler 27 again via the discharge pressure connecting pipe 29 from the high stage discharge pipe 24, and discharge refrigerant in the volume portion 27a. Separated from.

The refrigerating machine oil supplied to the high stage part 12 through the high stage oil return pipe 27h is not the total amount of the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27, but a part of the refrigerating machine oil. Since the amount of the refrigerating machine oil supplied through the suction pressure space is larger, the refrigerating machine oil separated from the discharged refrigerant by the discharge muffler 27 is supplied to the high stage 12 and returned to the discharge muffler 27 to be separated from the discharged refrigerant. Even if the circulation is performed, the refrigerating machine oil in the oil sump 17 is not exhausted.

Here, the low-stage oil return pipe 27g and the high-stage oil return pipe 27h may be formed by connecting a plurality of pipes, and the low-stage oil return pipe 27g communicates from the high pressure space to the low pressure space. Since a part of the refrigeration oil or the discharged refrigerant, which is a fluid passing therethrough, is decompressed to a low pressure, it is preferably formed by a capillary tube or a decompression valve interposed in the middle. Similarly, since the high stage oil return pipe 27h communicates from the high pressure space to the intermediate pressure space, a part of the refrigeration oil or discharged refrigerant that is a fluid passing therethrough is reduced to the intermediate pressure. It is preferable to interpose a pressure reducing valve in the middle.

In the compressor 4, the two oil return pipes 27g and 27h are opened to the inside of the volume portion 27a. Therefore, when the bottom surface of the volume portion 27a is spherical, the central portion positioned most downward in the axial direction of the volume portion 27a. It is difficult to braze or weld the two oil return pipes 27g and 27h in the vicinity. A distance is required between the positions at which the two oil return pipes 27g and 27h are attached to the bottom surface of the volume portion 27a. Therefore, a flat surface portion is formed on the bottom surface of the volume portion 27a, and two oil return pipes 27g and 27h are installed on the flat surface portion, or the spherical radius of the bottom surface of the volume portion 27a is increased to be separated into the volume portion 27a. In addition, it is necessary to prevent or reduce the amount of refrigerating machine oil to a small amount.

In the fourth embodiment, the refrigerating machine oil separated from the discharge refrigerant by the discharge muffler 27 does not flow into the sealed container 10 and return to the oil sump 17, but instead of the low-stage compression chamber and the high-stage section of the low-stage section 11. The total amount is divided into 12 high-stage compression chambers. In the first and second embodiments, the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 is returned to the oil sump 17 and the refrigerating machine oil is supplied from the oil sump 17 to the low stage part 11 or the high stage part 12. However, in the fourth embodiment, the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 is supplied to the low-stage compression chamber of the low-stage section 11 and the high-stage compression chamber of the high-stage section 12 before returning to the oil sump 17. It is done.

Since the compressor 4 supplies the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 to the low-stage compression chamber of the low-stage part 11 together with the low-pressure refrigerant via the low-stage oil return pipe 27g and the low-stage suction pipe 20. The sealing performance of the low-stage compression chamber is improved, and the lubricity of the sliding portion of the low-stage portion 11 is improved. Further, a part of the refrigeration oil separated from the refrigerant discharged by the discharge muffler 27 is supplied to the high-stage compression chamber of the high-stage portion 12 together with the intermediate-pressure refrigerant through the high-stage oil return pipe 27h and the high-stage suction pipe 23. Since the sealing performance of the high-stage compression chamber is improved and the lubricity of the sliding portion of the high-stage portion 12 is improved, the effect of becoming a highly efficient and highly reliable compressor can be obtained.

Further, the pulsation of the discharged refrigerant discharged from the high stage portion 12 can be sufficiently silenced by the discharge muffler 27, and most of the refrigerating machine oil separated from the discharged refrigerant by the oil separation mechanism is transferred from the low stage portion 11 into the sealed container 10. Since the oil is discharged and separated in the airtight container 10, it can be returned to the oil sump 17 at the bottom of the airtight container 10, avoiding the danger of exhausting the refrigerating machine oil in the oil sump 17, and storing the refrigerating machine oil in the oil sump 17. The amount can be maintained at an appropriate amount.

Further, similar to the compressor 1, when separating the oil in the discharge muffler 27, the centrifugal oil of the swirling flow is used to separate the refrigerating machine oil from the discharged refrigerant, so that the pressure loss of the discharged refrigerant can be reduced, and the discharge muffler Space saving can be achieved by integrating with the compressor body, and the effect of improving the degree of freedom and productivity of designing the refrigerant circuit can be obtained.

Also in the fourth embodiment, the configurations of the supply pipe 27b, the discharge pipe 27c, the intermediate pressure connection pipe 25, the discharge pressure connection pipe 29, the bracket 26, and the like of the discharge muffler 27 are the same as the various configurations described in the first embodiment. As in the compressor 1, the refrigerant discharged from the discharged refrigerant is separated from the discharged refrigerant by using the swirling flow as a swirling flow and using the centrifugal force of the swirling flow. The relationship between the opening positions of the intermediate pressure outlet pipe 22 and the low-stage discharge pipe 21 inside the sealed container 10 is the same as that of the first embodiment.

The compressor 4 includes a refrigerant outlet pipe 22, and after the intermediate pressure refrigerant inside the sealed container 10 is led out to the outside of the sealed container 10, one end thereof passes through a high-stage suction pipe 23 positioned at the outside of the sealed container 10. The high stage compression mechanism 12 is designed to be sucked in, but the refrigerant outlet pipe 22 is not provided, the high stage suction pipe is accommodated in the sealed container 10, and one end of the high stage suction pipe is opened in the sealed container 10. However, the same effect can be obtained by applying to an internal circulation type internal intermediate pressure type two-stage compression compressor configured to connect the other end to the high-stage compression mechanism section 12.

Embodiment 5 FIG.
FIG. 8 is an explanatory longitudinal sectional view showing an internal intermediate pressure type two-stage compression compressor 5 according to Embodiment 5 for carrying out the present invention. 8 that are the same as those in FIG. 7 are the same or similar parts as the compressor 4 shown in FIG. 7, and a description thereof is omitted here. The compressor 5 shown in FIG. 8 is the same in that the refrigerating machine oil separated from the refrigerant discharged by the discharge muffler 27 is supplied separately to the suction pressure space and the intermediate pressure space that is the suction space of the high stage portion 12. 7 differs from the compressor 4 in that there is one opening to the inside of the volume 27a of the oil return pipe 27k, the oil return pipe 27k branches off from the middle of the oil return pipe 27k, and one of them is a low-stage suction pipe. 20, and the other is connected to the high-stage suction pipe 23.

The oil return pipe 27k is installed such that the base pipe part 27ka opens into the volume part 27a and the opening position thereof is substantially at the center of the bottom surface of the volume part 27a. The opening of the volume part 27a of the oil return pipe 27k is only the opening of the base pipe part 27ka, and the oil return pipe 27k is brazed or welded to the volume part 27a at only one place. Can be installed in the center. And two piping branches from the other end (countervolume part 27a side) of the base tube part 27ka. One is a low-stage oil return pipe portion 27 kb that opens to a low-stage intake pipe 20 that is a suction pressure space, and the other is a high-stage that opens to a high-stage suction pipe 23 that is a suction space (intermediate pressure space) of the high stage portion 12. A step oil return pipe portion 27kc.

The low-stage oil return pipe portion 27 kb may be connected so as to open to the low-pressure pipe 50 of the refrigerant circuit, or penetrates the sealed container 10 and opens into a low-pressure space such as a low-stage suction chamber of the low-stage portion 11. You may connect as you do. Further, the high-stage oil return pipe portion 27kc may be connected so as to open to the intermediate pressure connection pipe 25 or the refrigerant outlet pipe 22, and penetrates the sealed container 10 to form a high-stage suction chamber of the high-stage section 12 or the like. The intermediate pressure space may be connected so as to open.

The low stage oil return pipe part 27kb and the high stage oil return pipe part 27kc may be formed by connecting a plurality of pipes, and the low stage oil return pipe part 27kb communicates from the high pressure space to the low pressure space. Since a part of the refrigeration oil or the discharged refrigerant, which is a fluid passing therethrough, is decompressed to a low pressure, it is preferably formed by a capillary tube or a pressure reducing valve interposed in the middle. Similarly, since the high-stage oil return pipe portion 27kc communicates from the high pressure space to the intermediate pressure space, a part of the refrigerating machine oil or discharged refrigerant that is a fluid passing therethrough is reduced to the intermediate pressure. Or a pressure reducing valve in the middle.

The base tube portion 27ka may also be formed by connecting a plurality of pipes. The base tube portion 27ka is formed by a capillary tube, or the pressure is reduced to an intermediate pressure by interposing a pressure reducing valve in the middle to return the high stage oil. The pipe portion 27kc may be allowed to pass without being reduced, and the low-stage oil return pipe portion 27kb may be further reduced to the suction pressure.

Since the compressor 5 is configured with the oil return pipe 27k as described above, in addition to the effects of the compressor 4 shown in the fourth embodiment, even if the bottom surface of the volume portion 27a is formed in a spherical shape, Since the oil return pipe 27k can be opened at the central portion, which is the lowest position in the axial direction, it is possible to avoid the refrigeration oil separated from the discharged refrigerant from staying inside the volume portion 27a. In addition, since it is not necessary to form a flat surface portion on the bottom surface of the volume portion 27a, the process for forming the flat surface portion can be eliminated when the volume portion 27a is press-molded, so that the manufacturing cost can be reduced.

The compressor 5 includes a refrigerant outlet pipe 22, and after the intermediate pressure refrigerant inside the sealed container 10 is led out to the outside of the sealed container 10, one end thereof passes through a high-stage suction pipe 23 positioned at the outside of the sealed container 10. The high stage compression mechanism 12 is designed to be sucked in, but the refrigerant outlet pipe 22 is not provided, the high stage suction pipe is accommodated in the sealed container 10, and one end of the high stage suction pipe is opened in the sealed container 10. However, the same effect can be obtained by applying to an internal circulation type internal intermediate pressure type two-stage compression compressor configured to connect the other end to the high-stage compression mechanism section 12.

The compressors shown in the first to fifth embodiments suck carbon dioxide as a refrigerant and compress it. For example, the compressor is used in a refrigerant circuit such as a heat pump type hot water supply apparatus using carbon dioxide as a refrigerant. It is well known that carbon dioxide has a higher operating pressure than conventional refrigerants such as HFC and HC (hydrocarbon). Since the operating pressure is high, the pressure pulsation of the discharged refrigerant (high-pressure refrigerant) compressed and discharged by the compression mechanism section is also relatively larger than that of the conventional refrigerant.

For this reason, in order to sufficiently silence the pulsation of the discharged refrigerant, a larger volume is required as a muffler (silence) space. The volume part 27a of the discharge muffler 27 described above can effectively utilize the entire internal space of the volume part 27a as one muffler space without partitioning the internal space up and down. It possesses an internal volume that can mute pressure pulsations over a wide frequency range and can sufficiently mute pulsations. In general, the muffler has a larger space volume, and in particular, the effect of silencing the pressure pulsation component in the low frequency region is higher. The discharge muffler 27 can be used as the muffler space largely because the entire inner space of the volume portion 27a is difficult to mute. A silencing effect in a low frequency range such as 1 kHz or less is obtained, and the noise can be muted over a wide frequency range.

Since carbon dioxide has a high operating pressure, there is a large pressure difference before and after compression in the compression mechanism, and refrigerant after compression or during compression leaks from the compression chamber to the suction chamber or is compressed and discharged by the compression mechanism. Leakage to the compression chamber and the suction chamber during the compression of the refrigerant tends to increase compared to the conventional refrigerant. Therefore, in order to reduce these leaks, it is necessary to positively supply the refrigerating machine oil to the suction chamber and the compression chamber of the compression mechanism section, and to improve the sealing performance of the suction chamber and the compression chamber by the oil. In a compressor using carbon dioxide as a refrigerant, more refrigeration oil is supplied to the compression chamber than in the case of a conventional refrigerant.

As a result, the refrigerant discharged from the compression mechanism section contains more refrigeration oil than in the conventional refrigerant. If a large amount of refrigerating machine oil is contained in the refrigerant discharged to the outside of the hermetic container 10, the refrigerating machine oil is separated from the refrigerant and recovered and returned to the inside of the hermetic container 10. Since the refrigerating machine oil will be depleted, an oil separation mechanism is required that separates and collects the refrigerating machine oil from the discharged refrigerant and returns it to the inside of the sealed container 10.

A so-called baffle plate system comprising an oil separator that vertically divides an internal space as disclosed in Patent Document 1 and separating a refrigerating machine oil contained in the discharged refrigerant by contacting a high-pressure discharged refrigerant passing through the oil separator. In this oil separation mechanism, the refrigeration oil can be separated, but the internal space is separated by the oil separator, so that the volume of each divided space is reduced, and a small capacity space is substantially reduced. It becomes a multistage muffler that passes continuously. And since the individual muffler space volume of the substantial multistage muffler is small, the pressure pulsation component on the low frequency side cannot be silenced, and the pulsation of the discharged refrigerant cannot be sufficiently silenced.

However, in the compressor discharge muffler 27 shown in the first to fifth embodiments, the oil separation mechanism does not divide the space volume of the volume portion 27a, and uses the entire volume without changing the space volume of the volume portion 27a. Can be separated from the high-pressure discharge refrigerant, and the entire volume of the internal space can be used as a single muffler space, so it becomes a large-volume muffler, and the low-frequency pressure pulsation component of the high-pressure discharge refrigerant can be silenced, A silencing effect in a wide frequency range can be obtained, and the pulsation of the discharged refrigerant can be sufficiently silenced.

In a compressor that sucks in carbon dioxide as a refrigerant, compresses and discharges it, a large amount of refrigeration oil is supplied to the compression chamber to improve the sealing performance. Therefore, the refrigeration oil contained in the high-pressure discharge refrigerant must be separated and recovered. In addition, since the pressure pulsation of the discharged refrigerant is large, the pulsation of the discharged refrigerant must be silenced with a muffler having a large space volume. Since the discharge muffler 27 of the compressor shown in Embodiments 1 to 5 can achieve both of them, it is particularly effective for a compressor using carbon dioxide as a refrigerant, for example, a compressor used in a heat pump hot water supply device. is there. However, the present invention is not limited to carbon dioxide, but can be applied to HFC refrigerants and HC refrigerants that are currently mainly used for refrigeration and air conditioning, and the same effects can be achieved. Similarly, the refrigerating machine oil is not limited to the PAG oil, and refrigerating machine oil adapted to the refrigerant to be used may be used.

Although all the compressors shown in the first to fifth embodiments have been described as internal intermediate pressure type two-stage compression type rotary compressors, the present invention is not limited to this, and the compression mechanism is not a rotary type, but a reciprocating type or a scroll type. Even in this case, the same effect can be obtained even if the inside of the sealed container 10 is not set to an intermediate pressure, and the pressure is low (suction pressure), or the compression mechanism is disposed above the electric motor. In the first to third embodiments, the same effect can be obtained not only in the two-stage compression type but also in a compressor in which a single-stage compression mechanism is housed in the sealed container.

Moreover, although the compressor shown to Embodiment 1-5 hold | maintained the discharge muffler 27 on the outer surface of the airtight container 10, space saving cannot be achieved, but discharge with the swirl type oil separation function of this invention is achieved. Even if the muffler is not held in the sealed container 10 and installed outside the sealed container 10, the same effect can be obtained. Further, for example, the discharge muffler with a swirl type oil separation function of the present invention is configured to be housed in the sealed container 10 such that the volume part is configured by a space surrounded by the inner surface of the sealed container 10 and the outer surface of the compression mechanism unit. The same effect can be obtained.

The expansion type muffler that is silenced at the volume portion, such as the discharge muffler 27 of the present invention, has an influence of the volume of the muffler volume portion on the silencing of the pulsation in a low frequency region with a long wavelength. Become. Since the carbon dioxide refrigerant has a higher sound speed in the refrigerant and the wavelength tends to be longer than that of the conventional refrigerant such as R410A, the frequency range in which the influence of the volume of the muffler volume is dominant is widened. And the expansion type muffler tends to have a greater silencing effect on low-frequency pressure pulsations as the volume of the muffler volume increases. Therefore, in the discharge muffler 27 with the swirling flow type oil separation function of the present invention, the volume of the internal space of the volume portion 27a is preferably 10 times or more the stroke volume of the compression mechanism portion.

In order to separate the refrigerating machine oil contained in the high-pressure refrigerant by turning the high-pressure refrigerant inside the volume 27a, the discharge pipe is used after the high-pressure refrigerant is supplied into the volume 27a from the supply pipe 27b. It is necessary to cause the high-pressure refrigerant to make an appropriate number of turns before entering 27c. For this purpose, the axial distance between the refrigerant blowing position of the supply pipe 27b and the refrigerant entering position of the discharge pipe 27c is determined by the volume portion. It is desirable that it is more than the diameter of the inner surface of 27a.

Even if the oil separation function provided in the discharge muffler is not a swirling flow type, and other oil separation functions such as the baffle plate method disclosed in Patent Document 1, for example, the oil return pipe of the discharge muffler enters the inside of the sealed container. By making the opening position and the location where the oil return pipe supplies the refrigerating machine oil separated from the discharged refrigerant into the positions and places shown in the first to fifth embodiments, the refrigerating machine oil separated from the high-pressure discharged refrigerant can be reliably obtained. The compressor can be returned to the oil reservoir at the bottom of the closed container, and the highly efficient compressor improves the effect of becoming a highly reliable compressor without exhaustion of the oil in the oil reservoir of the oil reservoir and the sealing performance of the compression chamber of the compression mechanism The following effects can be obtained.

It is a longitudinal cross-sectional view of the compressor which shows Embodiment 1 of this invention. It is a top view of the principal part of the compressor shown in FIG. It is a schematic diagram which shows the Example in the case of attaching the supply pipe | tube 27b to the volume part 27a side surface. FIG. 4 is an explanatory diagram showing the flow of discharged refrigerant inside the discharged muffler 27. It is a longitudinal cross-sectional view of the compressor which shows Embodiment 2 of this invention. It is a longitudinal cross-sectional view of the compressor which shows Embodiment 3 of this invention. It is a longitudinal cross-sectional view of the compressor which shows Embodiment 4 of this invention. It is a longitudinal cross-sectional view of the compressor which shows Embodiment 5 of this invention.

Explanation of symbols

  1, 2, 3, 4, 5 Compressor, 10 Sealed container, 10a Cylindrical container, 10b Upper lid, 10c Bottom lid, 11 Low stage compression mechanism (low stage), 12 High stage compression mechanism (high stage) , 13 Motor, 13a Stator, 13b Rotor, 14 Rotating shaft, 17 Oil sump, 20 Low stage suction pipe, 21 Low stage discharge pipe, 22 Refrigerant outlet pipe, 23 High stage suction pipe, 24 High stage discharge pipe, 25 Intermediate pressure connection pipe, 26 Bracket, 26a Curved part, 26b Holding part, 27 Discharge muffler, 27a Volume part, 27b Supply pipe, 27c Discharge pipe, 29 Discharge pressure connection pipe, 30 Space A, 27d, 27e, 27f, 27k Oil Return pipe, 27g Low stage oil return pipe, 27h High stage oil return pipe, 27ka Base pipe part, 27kb Low stage oil return pipe part, 27kc High stage oil return pipe part, 50 Low pressure pipe, 51 High pressure pipe.

Claims (5)

An electric motor, is composed of a low-stage compression mechanism portion and the high-stage compression mechanism, the sealed container and a compression mechanism for ejecting compressed to high pressure refrigerant is driven by coupled rotational shaft to the electric motor The low-stage compression mechanism unit compresses the low-pressure refrigerant to an intermediate pressure and discharges it into the sealed container. The inside of the sealed container is used as an intermediate pressure. A compressor that compresses and discharges the refrigerant to a high pressure in the high-stage compression mechanism ,
A high- pressure discharge refrigerant containing refrigeration oil discharged from the high- stage compression mechanism is supplied, and a volume portion having a volume that silences the pulsation of the high-pressure discharge refrigerant;
Blown discharge refrigerant of the high pressure along the inner surface of the volume, a supply pipe for supplying the refrigerant discharged the pressure in the internal space of the volume to the swirling flow,
Provided at the bottom of the volume, the return oil is discharged refrigerating machine oil separated from the discharge refrigerant of the high pressure in the inner space of the volume by the centrifugal force of the swirling flow to the outside of the volume from the volume Tube,
Wherein said feed pipe inside the volume is open one to the bottom side of the volume than to position blown the discharge refrigerant of the high pressure, the refrigerating machine oil has been separated is open and the other to the outside of the volume A discharge pipe for discharging high-pressure discharge refrigerant from the internal space of the volume part to the outside;
A discharge muffler comprising :
The refrigerating machine oil discharged from the volume part to the oil return pipe is supplied to the compression chamber of the low-stage compression mechanism part together with the low-pressure refrigerant, and the refrigerating machine oil discharged from the volume part to the oil return pipe A part of the compressor is supplied to the compression chamber of the high-stage compression mechanism along with the intermediate pressure refrigerant . An electric motor, is composed of a low-stage compression mechanism portion and the high-stage compression mechanism, the sealed container and a compression mechanism for ejecting compressed to high pressure refrigerant is driven by coupled rotational shaft to the electric motor while housed inside of said at low-stage compression mechanism compresses low-pressure refrigerant to an intermediate pressure discharged into the interior of the sealed container, and with the closed container inside the intermediate pressure, the sealed container inside the intermediate a discharges that compressor and compressed to a high pressure Te before Symbol high-stage compression mechanism to the refrigerant pressure,
A high- pressure discharge refrigerant containing refrigeration oil discharged from the high- stage compression mechanism is supplied, and a volume portion having an oil separation function for separating the refrigeration oil from the high-pressure discharge refrigerant;
A supply pipe for supplying the high-pressure discharge refrigerant to the internal space of the volume part;
Provided at the bottom of the volume, and the oil return pipe for discharging the refrigerating machine oil separated from the discharge refrigerant of the high pressure in the inner space of the volume outside of the volume from the volume,
A discharge pipe for discharging the high-pressure discharge refrigerant from which the refrigerating machine oil is separated from the internal space of the volume part to the outside, and provided outside the sealed container,
The by refrigeration oil discharged to the oil return pipe from the front Symbol volume, The rewritable supplied with the low-pressure refrigerant into the compression chamber of the low-stage compression mechanism, which is discharged to the pipe returning the oil from the volume refrigeration A compressor characterized in that a part of the machine oil is supplied to the compression chamber of the high-stage compression mechanism section together with the intermediate pressure refrigerant . The compressor according to claim 1 , wherein the discharge muffler is held on an outer surface of the sealed container. Two oil return pipes are provided,
One oil return pipe is connected so that one end opens to the internal space of the volume part and the other end opens to the low pressure space of the low-stage compression mechanism part,
The other oil return pipe is connected so that one end thereof opens to the internal space of the volume part and the other end opens to the suction space of the high-stage compression mechanism part. The compressor in any one of. The oil return pipe has a base pipe part whose one end opens into the internal space of the volume part, and a low-stage oil return pipe part and a high-stage oil return pipe part branched from the other end of the base pipe part. ,
The low stage oil return pipe part is connected to open to the low pressure space of the low stage compression mechanism part,
The compressor according to any one of claims 1 to 3, wherein the high-stage oil return pipe portion is connected so as to open to a suction space of the high-stage compression mechanism portion.

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