JP2013104341A - Two stage compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lubricating oil from stagnating in a low stage side muffler space, and also prevent a rear head from deforming.SOLUTION: A two stage compressor 1 has a low stage side compressing mechanism 11, a high stage side compressing mechanism 12 for further compressing a refrigerant compressed in the low stage side compressing mechanism 11, and a casing 2 for housing the two compressing mechanisms, and the low stage side compressing mechanism 11 has a low stage side cylinder 23 having a low stage side compressing chamber 23a, a rear head 22 arranged below the low stage side cylinder 23, and a rear muffler 21 arranged below the rear head 22 and forming a rear muffler space M1 between the rear head 22 and the same. A low stage discharge pipe 14 for discharging the refrigerant in the low stage side muffler space M1 to the outside of the casing 2 is connected to the rear muffler 21.

Description

  The present invention relates to a two-stage compressor including a low-stage compression mechanism and a high-stage compression mechanism.

  Conventionally, a two-stage compressor including a low-stage compression mechanism, a high-stage compression mechanism, and a casing that houses these two compression mechanisms is known (see, for example, Patent Document 1). The refrigerant compressed by the low-stage compression mechanism is discharged to the outside of the casing, and then supplied to the high-stage compression mechanism via an external muffler or the like. The refrigerant compressed by the high-stage compression mechanism is discharged into the casing and then discharged out of the casing. In addition, lubricating oil for smoothing the movement of the sliding portion of the compression mechanism is stored in a lower portion in the casing. The lubricating oil passes through the low-stage compression mechanism and the high-stage compression mechanism together with the refrigerant, and then is returned to the lower portion of the casing.

  The low-stage side compression mechanism includes a low-stage side cylinder having a low-stage side compression chamber, a rear head arranged below the low-stage side cylinder, and a rear muffler arranged below the rear head. A low-stage muffler space is formed between the rear head and the rear muffler, from which the refrigerant compressed in the low-stage compression chamber is discharged. The low-stage muffler space is provided to suppress refrigerant discharge pulsation and to reduce noise associated with refrigerant discharge. In the two-stage compressor of Patent Document 1, a low-stage discharge pipe for discharging the refrigerant in the low-stage muffler space is connected to the side portion of the rear head. The rear head and the rear muffler are fixed to the rear cylinder with bolts.

JP 2010-223190 A

In the configuration in which the low stage discharge pipe is connected to the side portion of the rear head, the bottom of the low stage side muffler space is at a lower position than the low stage discharge pipe. Therefore, the lubricating oil at a position lower than the low stage discharge pipe in the low stage side muffler space cannot be discharged from the low stage discharge pipe, and the lubricating oil accumulates in the low stage side muffler space.
When lubricating oil accumulates in the low-stage muffler space, the effective volume of the low-stage muffler space is reduced, so that the effect of suppressing the discharge pulsation of refrigerant and reducing noise is reduced. Further, since the refrigerant is heated by the lubricating oil accumulated in the low-stage muffler space, the compressor efficiency is lowered. Further, since the amount of lubricating oil stored in the lower part of the casing is reduced, there is a case where a sufficient amount of lubricating oil cannot be supplied to the compression mechanism, and reliability is lowered.

  Further, since a hole for connecting the low-stage discharge pipe is formed on the side portion of the rear head, there arises a problem that when the rear head is bolted to the rear cylinder, the rear head is easily deformed in the vicinity of the hole.

  In view of the above, an object of the present invention is to provide a two-stage compressor that can prevent the lubricating oil from accumulating in the low-stage muffler space and can suppress the deformation of the rear head.

  A two-stage compressor according to a first invention includes a low-stage compression mechanism, a high-stage compression mechanism that further compresses the refrigerant compressed by the low-stage compression mechanism, and a casing that houses these two compression mechanisms. The low-stage compression mechanism includes a low-stage cylinder having a low-stage compression chamber, a rear head disposed below the low-stage cylinder, and the rear head A low-stage discharge pipe that is disposed on the lower side and includes a rear muffler that forms a low-stage muffler space with the rear head, and causes the refrigerant in the low-stage muffler space to be discharged out of the casing to the rear muffler. Are connected.

In this two-stage compressor, since the low-stage discharge pipe is connected to the rear muffler, the lower stage-side muffler space is positioned lower than when the low-stage discharge pipe is connected to the rear head disposed above the rear muffler. The refrigerant and the lubricating oil can be discharged from. Therefore, it is possible to prevent the lubricating oil from accumulating in the low-stage muffler space.
In addition, since it is not necessary to provide a hole for connecting the low-stage discharge pipe to the rear head, the rigidity of the rear head is higher than when the hole is provided. Therefore, deformation of the rear head due to bolt fastening can be suppressed.

  A two-stage compressor according to a second invention is characterized in that, in the first invention, the refrigerant in the low-stage muffler space is discharged from the lower part of the low-stage muffler space. And

In this two-stage compressor, it is possible to more reliably prevent the lubricating oil from accumulating in the low-stage side muffler space.
“Discharged from the lower part of the lower muffler space” means that refrigerant is discharged from an opening formed in the bottom surface of the surface surrounding the lower muffler space, or the lower muffler space. Is that the refrigerant is discharged from an opening formed at the lower end of the side surface.

  A two-stage compressor according to a third invention is the two-stage compressor according to the second invention, wherein the rear head has a discharge port through which the refrigerant in the low-stage side compression chamber is discharged into the low-stage side muffler space. The refrigerant in the stage side muffler space is configured to be discharged from a position not facing the discharge port of the rear head in a lower part of the low stage side muffler space.

  In this two-stage compressor, it is possible to prevent the lubricating oil from being difficult to be discharged from the low-stage muffler space due to the jet power of the refrigerant discharged from the rear head discharge port to the low-stage muffler space.

  A two-stage compressor according to a fourth invention is characterized in that, in any one of the first to third inventions, the low-stage discharge pipe is connected to a side portion of the rear muffler.

  In this two-stage compressor, when the low-stage discharge pipe is provided on the side of the casing, the portion of the low-stage discharge pipe in the casing can be straightened, so the low-stage discharge pipe is attached to the rear muffler in the casing. Easy to connect.

  A two-stage compressor according to a fifth aspect of the present invention is the first to fourth aspects of the invention, wherein the rear muffler has a discharge passage that allows the low-stage side muffler space and the low-stage discharge pipe to communicate with each other. The inlet of the discharge path is formed on the upper surface of the rear muffler.

  In this two-stage compressor, the refrigerant in the low stage side muffler space can be discharged from the lower part of the low stage side muffler space.

  As described above, according to the present invention, the following effects can be obtained.

In the first aspect of the invention, since the low-stage discharge pipe is connected to the rear muffler, the low-stage side muffler space is lower than the case where the low-stage discharge pipe is connected to the rear head disposed above the rear muffler. Refrigerant and lubricating oil can be discharged. Therefore, it is possible to prevent the lubricating oil from accumulating in the low-stage muffler space.
In addition, since it is not necessary to provide a hole for connecting the low-stage discharge pipe to the rear head, the rigidity of the rear head is higher than when the hole is provided. Therefore, deformation of the rear head due to bolt fastening can be suppressed.

  In the second invention, it is possible to more reliably prevent the lubricating oil from accumulating in the low-stage muffler space.

  In the third aspect of the invention, it is possible to prevent the lubricating oil from becoming difficult to be discharged from the low-stage muffler space due to the jet power of the refrigerant discharged from the discharge port of the rear head to the low-stage muffler space.

  In the fourth aspect of the invention, when the low-stage discharge pipe is provided on the side of the casing, the portion of the low-stage discharge pipe in the casing can be made straight, so the low-stage discharge pipe is connected to the rear muffler in the casing. It's easy to do.

  In the fifth aspect of the invention, the refrigerant in the low stage side muffler space can be discharged from the lower part of the low stage side muffler space.

It is sectional drawing of the two-stage compressor which concerns on 1st Embodiment of this invention. It is the figure which looked at the rear head from the bottom. It is the sectional view on the AA line of FIG. It is sectional drawing of the two-stage compressor which concerns on 2nd Embodiment of this invention. (A) is a fragmentary sectional view of the two-stage compressor which concerns on other embodiment of this invention, (b) is the BB sectional drawing of (a).

<First Embodiment>
The first embodiment of the present invention will be described below.
As shown in FIG. 1, the two-stage compressor 1 of this embodiment includes a casing 2, a compression unit 10 and a drive mechanism 6 disposed in the casing 2. The compression unit 10 includes a low-stage compression mechanism 11 and a high-stage compression mechanism 12. In the two-stage compressor 1, the refrigerant (for example, CO ₂ refrigerant) introduced from the low-stage suction pipe 13 is compressed by the low-stage compression mechanism 11, and further compressed by the high-stage compression mechanism 12 to be discharged from the discharge pipe. 16 is discharged.

  The casing 2 is a cylindrical container closed at both ends, and inside the casing 2, a drive mechanism 6 and a compression unit 10 are arranged side by side. In the lower part of the casing 2, lubricating oil L for smoothing the operation of the sliding portion of the compression unit 10 is stored. Further, on the side of the casing 2, a low-stage suction pipe 13 for sucking refrigerant into the low-stage compression mechanism 11 of the compression unit 10, and the refrigerant compressed by the low-stage compression mechanism 11 are placed outside the casing 2. A low stage discharge pipe 14 for discharging and a high stage suction pipe 15 for sucking refrigerant into the high stage side compression mechanism 12 are provided. In the upper part of the casing 2, a current is supplied to a discharge pipe 16 for discharging the refrigerant discharged from the high-stage compression mechanism 12 (refrigerant in the casing 2) and a coil of a stator 7 b described later of the drive mechanism 6. Terminal terminals 3 are provided. In FIG. 1, the wiring connecting the coil and the terminal terminal 3 is omitted. A plurality of leg portions 4 are provided at the lower portion of the casing 2. The casing 2 is fixed to the bottom plate of the outdoor unit of the air conditioner, for example, by the legs 4.

  The drive mechanism 6 is provided to drive the low-stage compression mechanism 11 and the high-stage compression mechanism 12 of the compression unit 10, and includes a motor 7 serving as a drive source and a shaft 8 attached to the motor 7. It is composed of In FIG. 1, hatching indicating a cross section of the motor 7 is omitted.

  The motor 7 includes a substantially annular stator 7b fixed to the inner peripheral surface of the casing 2, and a rotor 7a disposed on the radially inner side of the stator 7b via an air gap. The rotor 7a has a magnet (not shown), and the stator 7b has a coil. The motor 7 rotates the rotor 7a by an electromagnetic force generated by passing a current through the coil. Further, the outer peripheral surface of the stator 7b is not in close contact with the inner peripheral surface of the casing 2 over the entire circumference. The outer peripheral surface of the stator 7b extends in the vertical direction and communicates with the upper and lower spaces of the motor 7. A plurality of recesses (not shown) are formed side by side in the circumferential direction.

  The shaft 8 is fixed to the inner peripheral surface of the rotor 7a and rotates integrally with the rotor 7a. Further, the shaft 8 has eccentric portions 8a and 8b at a position in a low-stage side compression chamber 23a, which will be described later, and a position in a high-stage side compression chamber 26a, respectively. The eccentric portions 8 a and 8 b are both formed in a columnar shape, and the axis thereof is eccentric from the rotation center of the shaft 8. Pistons 24 and 27 of the compression unit 10 are mounted on the eccentric portions 8a and 8b, respectively.

  An oil supply passage 8c is formed inside the lower half of the shaft 8. The oil supply path 8c extends in the vertical direction and branches in the radial direction of the shaft 8 at several locations. At the lower end of the shaft 8, a spiral blade-shaped pump member (not shown) that sucks the lubricating oil L into the oil supply passage 8 c as the shaft 8 rotates is provided. The lubricating oil L sucked up from the lower end of the oil supply passage 8 c by the pump member is discharged from the side surface of the shaft 8 and supplied to the compression unit 10.

  The compression unit 10 is disposed in a rear muffler 21, a rear head 22, a low-stage cylinder 23, a piston 24 disposed in the low-stage cylinder 23, a middle plate 25, a high-stage cylinder 26, and a high-stage cylinder 26. A piston 27, a front head 28, and a front muffler 29 are provided. The low-stage compression mechanism 11 includes a low-stage cylinder 23, a piston 24, a middle plate 25, a rear head 22, and a rear muffler 21. The high-stage compression mechanism 12 is disposed above the low-stage compression mechanism 11 and includes a high-stage cylinder 26, a piston 27, a middle plate 25, a front head 28, and a front muffler 29. .

  The low stage side cylinder 23, the middle plate 25, and the high stage side cylinder 26 are fixed to the inner peripheral surface of the casing 2. The low-stage side cylinder 23, the middle plate 25, and the high-stage side cylinder 26 allow the refrigerant and the lubricating oil L to pass through radially outside the low-stage side compression chamber 23a and the high-stage side compression chamber 26a when viewed in the vertical direction. An oil return passage (not shown) is provided.

  A low-stage compression chamber 23 a that is a circular hole is formed at the center of the low-stage cylinder 23. A piston 24 is disposed in the low-stage compression chamber 23a. The piston 24 includes a roller and a blade that protrudes radially outward from the outer peripheral surface of the roller. The piston 24 divides the low-stage compression chamber 23a into two spaces. The low-stage cylinder 23 is formed with a suction path 23b for introducing the refrigerant into the low-stage compression chamber 23a. The tip of the low-stage suction pipe 13 is fitted in the suction path 23b.

  Similar to the low-stage cylinder 23, the high-stage cylinder 26 is formed with a high-stage compression chamber 26a and a suction passage 26b. A piston 27 similar to the piston 24 is disposed in the high-stage compression chamber 26a. The leading end of the high-stage suction pipe 15 is fitted in the suction path 26b.

  The middle plate 25 is disposed between the low-stage side cylinder 23 and the high-stage side cylinder 26, closes the upper end of the low-stage side compression chamber 23 a of the low-stage side cylinder 23, and The lower end of the high-stage compression chamber 26a is closed. The middle plate 25 is fixed to the low-stage cylinder 23 and the high-stage cylinder 26 by bolts.

  The rear head 22 is disposed below the low-stage cylinder 23, and the rear muffler 21 is disposed below the rear head 22. As shown in FIGS. 2 and 3, the rear muffler 21 and the rear head 22 have a plurality of bolt holes 41 and 33, and are fixed to the low-stage cylinder 23 by a plurality of bolts 50 inserted therethrough. FIG. 3 is a cross-sectional view taken along line AA in FIG. 1, but the casing 2, the low stage suction pipe 14, and the shaft 8 are omitted.

  The rear head 22 is a substantially annular member, and the shaft 8 is rotatably inserted through a hole in the center thereof. The upper surface of the rear head 22 closes the lower end of the lower stage compression chamber 23 a of the lower stage cylinder 23. As shown in FIG. 2, the rear head 22 has a discharge hole 30 for discharging the refrigerant compressed in the low-stage compression chamber 23a. A concave groove 31 is formed on the lower surface of the rear head 22. An outlet (discharge port) 30 a of the discharge hole 30 is formed at the bottom of the concave groove 31. Further, a valve mechanism 32 that opens and closes the outlet 30 a of the discharge hole 30 in accordance with the pressure in the low-stage compression chamber 23 a is provided in the concave groove 31.

  The rear muffler 21 is disposed below the rear head 22, and forms a low-stage muffler space M <b> 1 between the rear muffler 21 and the recessed groove 31 of the rear head 22. The rear muffler 21 is an annular plate member. The rear muffler 21 is formed with a discharge path 40 for discharging the refrigerant in the low-stage side muffler space M1.

  An inlet 40 a of the discharge path 40 is formed on the upper surface of the rear muffler 21. That is, the refrigerant in the low stage side muffler space M1 is discharged from the lower part of the low stage side muffler space M1. As shown in FIG. 3, the inlet 40 a of the discharge path 40 of the rear muffler 21 is formed at a position that does not face the outlet (discharge port) 30 a of the discharge hole of the rear head 22.

  Further, the outlet 40 b of the discharge passage 40 is formed on the side surface of the rear muffler 21. The outlet 40b side portion of the discharge path 40 extends in the horizontal direction. An end of the low-stage discharge pipe 14 is fitted into the outlet 40 b of the discharge path 40. Therefore, the low stage discharge pipe 14 is connected to the side of the rear muffler 21. The outlet 40b of the discharge path 40 and the hole through which the low-stage discharge pipe 14 formed in the side portion of the casing 2 is inserted are opposed to each other, and the low-stage discharge pipe 14 extends in the horizontal direction.

  The front head 28 is disposed on the upper side of the high stage side cylinder 26. The front head 28 is a substantially annular member, and the shaft 8 is rotatably inserted through a hole in the center thereof. The lower surface of the front head 28 closes the upper end of the high stage side compression chamber 26 a of the high stage side cylinder 26. The front head 28 is formed with a discharge hole (not shown) for discharging the refrigerant compressed in the high-stage compression chamber 26a. A valve mechanism (not shown) that opens and closes the outlet of the discharge hole according to the pressure in the high-stage compression chamber 26a is attached to the upper surface of the front head 28.

  The front muffler 29 is attached to the upper surface of the front head 28 with bolts, and forms a high-stage muffler space M2 between the front muffler 29 and the front head 28. The front muffler 29 has a double structure. Further, the front muffler 29 is formed with a muffler discharge hole (not shown) for discharging the refrigerant in the high-stage muffler space M2.

Next, the operation of the two-stage compressor 1 will be described.
In the compression unit 10, first, the refrigerant is supplied into the low-stage compression chamber 23 a of the low-stage compression mechanism 11 through the low-stage suction pipe 13. The refrigerant compressed in the low-stage compression chamber 23a is discharged into the low-stage muffler space M1, and then sent out of the casing 2 through the low-stage discharge pipe 14. The refrigerant passes through an external muffler and an intercooler (not shown), and then is supplied into the high-stage compression chamber 26a of the high-stage compression mechanism 12 via the high-stage suction pipe 15, and the high-stage compression chamber 26a. Is further compressed. The refrigerant compressed in the high-stage compression chamber 26a is discharged into the high-stage muffler space M2, and then discharged from the muffler discharge hole (not shown) of the front muffler 29 to the outside of the compression unit 10, and then the discharge pipe 16 is discharged to the outside of the casing 2.

  In the low-stage compression mechanism 11, when the shaft 8 is rotated by driving the motor 7, the roller of the piston 24 attached to the eccentric portion 8b of the shaft 8 is along the peripheral wall surface of the low-stage compression chamber 23a. Accordingly, the refrigerant is compressed in the low-stage compression chamber 23a. In the high-stage compression mechanism 12, as in the low-stage compression mechanism 11, the piston 27 attached to the eccentric portion 8a of the shaft 8 moves along the peripheral wall surface of the high-stage compression chamber 26a. The refrigerant is compressed in the stage side compression chamber 26a.

  In the two-stage compressor 1 of the present embodiment, since the low-stage discharge pipe 14 is connected to the rear muffler 21, compared to the case where the low-stage discharge pipe 14 is connected to the rear head 22 disposed above the rear muffler 21. Thus, the refrigerant and the lubricating oil L can be discharged from a lower position of the low-stage muffler space M1. Therefore, it is possible to prevent the lubricating oil L from accumulating in the low-stage muffler space M1.

  Further, since it is not necessary to provide a hole for connecting the low-stage discharge pipe 14 to the rear head 22, the rigidity of the rear head 22 is higher than that in the case where the hole is provided. Therefore, deformation of the rear head 22 can be suppressed when the rear muffler 21 and the rear head 22 are bolted to the low-stage cylinder 23.

  In the present embodiment, the inlet 40a of the discharge passage 40 is formed on the upper surface of the rear muffler 21, and the refrigerant in the low-stage side muffler space M1 is discharged from the lower part of the low-stage side muffler space M1. Therefore, it is possible to more reliably prevent the lubricating oil L from accumulating in the low-stage muffler space M1.

  In the present embodiment, the discharge port 30a for supplying the refrigerant to the low-stage muffler space M1 and the inlet 40a of the discharge passage 40 for discharging the refrigerant from the low-stage muffler space M1 are not opposed to each other. It is formed at a position that does not overlap when viewed from the axial direction of the shaft 8, and is configured such that the refrigerant in the low-stage muffler space M 1 is discharged from a position that does not face the discharge port 30 a of the rear head 22. . If the refrigerant in the low-stage muffler space M1 is discharged from a position facing the discharge port 30a of the rear head 22, the refrigerant discharged from the discharge port 30a to the low-stage muffler space M1. However, in this embodiment, the refrigerant in the lower muffler space M1 is discharged from the rear head 22 by the refrigerant in the lower muffler space M1 being difficult to be discharged from the discharge passage 40 of the rear muffler 21. Since it is configured to be discharged from a position that does not face the outlet 30a, the lubricating oil L is easily discharged from the low-stage muffler space M1.

  In the present embodiment, the low-stage discharge pipe 14 is connected to the side portion of the rear muffler 21 and penetrates the side portion of the casing 2. Therefore, since the part in the casing of the low stage discharge pipe 14 can be made linear, it is easy to connect the low stage discharge pipe 14 to the rear muffler 21 in the casing.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described. In addition, about the thing which has the structure similar to 1st Embodiment, the description is abbreviate | omitted suitably using the same code | symbol.
As shown in FIG. 4, the two-stage compressor 101 of the present embodiment is different from the first embodiment in the configuration of the rear muffler 121 and the low-stage discharge pipe 114, and the other configurations are the same as those in the first embodiment. .

  The rear muffler 121 is formed with a discharge path 140 for discharging the refrigerant in the low-stage muffler space M1. The inlet of the discharge path 140 is formed on the upper surface of the rear muffler 121. Therefore, the refrigerant in the low stage side muffler space M1 is discharged from the lower part of the low stage side muffler space M1. The discharge path 140 is formed so as to penetrate the rear muffler 121 in the vertical direction. The end of the low-stage discharge pipe 114 is fitted into the outlet of the discharge path 140. The low stage discharge pipe 114 penetrates the side part of the casing 2 in the horizontal direction, and a portion from the rear muffler 121 to the casing 2 has a bent shape.

  In the two-stage compressor 101 of the present embodiment, since the inlet of the low-stage discharge pipe 114 is formed on the upper surface of the rear muffler 121, the refrigerant in the low-stage side muffler space M1 is drawn from the lower part of the low-stage side muffler space M1. Can be discharged. In this embodiment, since the shape of the discharge path 140 is a shape penetrating the rear muffler 121 in the vertical direction, the discharge path 140 is easily formed. In addition, the same effect as the first embodiment can be obtained.

  As mentioned above, although embodiment of this invention was described, it should be thought that the specific structure of this invention is not limited to the said embodiment. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

  In the first and second embodiments, the low-stage discharge pipes 14 and 114 are configured to penetrate the side portions of the casing 2, but the low-stage discharge pipes are configured to penetrate the bottom portion of the casing 2. It may be. When the low-stage discharge pipe is connected to the lower part of the rear muffler 121 as in the second embodiment, the portion from the rear muffler 121 to the casing 2 of the low-stage discharge pipe is a straight line extending in the vertical direction. Therefore, it is easy to connect the low-stage discharge pipe to the rear muffler 121 in the casing 2.

  In the first and second embodiments, the low-stage muffler space M1 is formed by the concave groove 31 formed in the rear head 22 and the upper surface of the rear muffler 21, but the present invention is not limited to this configuration. For example, as shown in FIG. 5, the lower muffler space M <b> 1 may be formed by the concave groove 242 formed in the rear muffler 221 and the lower surface of the circular plate-like rear head 222. In the case of this modified form, the rear head 222 is formed with a discharge hole 230 for discharging the refrigerant compressed in the low stage side compression chamber 23a to the low stage side muffler space M1, and an outlet (discharge port) of the discharge hole 230. 230 a is formed on the lower surface of the rear head 222. Further, the rear muffler 221 is formed with a discharge path 240 for discharging the refrigerant in the low-stage muffler space M1.

  In FIG. 5, the inlet 240 a of the discharge path 240 is formed at the lower end of the side portion of the concave groove 242. That is, the inlet 240a is formed at the lower end of the side surface of the surface surrounding the low stage side muffler space M1, and the refrigerant in the low stage side muffler space M1 is discharged from the lower part of the low stage side muffler space M1. . In addition, the inlet 240a of the discharge channel 240 may be formed on the bottom surface of the groove 242 or may be formed above the lower end of the side portion of the groove 242.

  In FIG. 5, the outlet 240 b of the discharge path 240 is formed at the side of the rear muffler 221, and the low-stage discharge pipe 214 is connected to the side of the rear muffler 221, but the outlet 240 b of the discharge path 240. May be formed on the lower surface of the rear muffler 221, and the low-stage discharge pipe 214 may be connected to the lower portion of the rear muffler 221.

  By utilizing the present invention, it is possible to suppress the accumulation of lubricating oil in the low-stage muffler space and to suppress deformation of the rear head.

DESCRIPTION OF SYMBOLS 1 Two-stage compressor 2 Casing 11 Low stage side compression mechanism 12 High stage side compression mechanism 14 Low stage discharge pipe 21 Rear muffler 22 Rear head 23 Low stage side cylinder 23a Low stage side compression chamber 30a, 230a Outlet (discharge port) of discharge hole
40, 140, 240 Discharge path 40a, 240a Discharge path inlet M1 Low stage muffler space

Claims (5)

A two-stage compressor comprising a low-stage compression mechanism, a high-stage compression mechanism that further compresses the refrigerant compressed by the low-stage compression mechanism, and a casing that houses these two compression mechanisms,
The low-stage compression mechanism is
A low-stage cylinder having a low-stage compression chamber;
A rear head disposed below the low-stage cylinder;
A rear muffler disposed below the rear head and forming a low-stage muffler space with the rear head;
A two-stage compressor, wherein a low-stage discharge pipe for discharging the refrigerant in the low-stage side muffler space to the outside of the casing is connected to the rear muffler.   2. The two-stage compressor according to claim 1, wherein the refrigerant in the low-stage muffler space is configured to be discharged from a lower portion of the low-stage muffler space. The rear head has a discharge port for discharging the refrigerant in the low-stage side compression chamber to the low-stage side muffler space,
The refrigerant in the low stage side muffler space is configured to be discharged from a position not facing the discharge port of the rear head in a lower part of the low stage side muffler space. The two-stage compressor described.   The two-stage compressor according to any one of claims 1 to 3, wherein the low-stage discharge pipe is connected to a side portion of the rear muffler.   The rear muffler includes a discharge path that allows the low-stage muffler space and the low-stage discharge pipe to communicate with each other, and an inlet of the discharge path is formed on an upper surface of the rear muffler. Item 5. The two-stage compressor according to any one of Items 1 to 4.

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