JP2008038697A - Multiple stage rotary compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multiple stage rotary compressor reducing pressure pulsation generated in an intermediate connection part connecting a low stage side cylinder delivery port to a high stage side cylinder intake port, and evenly arranging bolts passing through the low stage side cylinder and the high stage side cylinder in an up-and-down direction to fasten the same. <P>SOLUTION: The multiple stage rotary compressor is provided with a plurality of compression mechanisms provided with: an annular cylinder having a crank shaft rotated by a motor at a center thereof; a roller eccentrically rotating in the cylinder keeping contact with the cylinder on one part by a plurality of crank shaft eccentric parts provided eccentrically on the crank shaft, and a vane abutting on an outside surface of the roller and dividing a space surrounded by an inner diameter surface of the cylinder and the outside surface into two. Pressure of refrigerant is sequentially increased by compression mechanisms connected in series. Rotary angle range in which the compression mechanism by which a high pressure refrigerant arrives performs compression stroke is wider than that of the compression mechanism by which a low pressure refrigerant arrives. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multistage rotary compressor used in, for example, a refrigerator-freezer, an air conditioner, a heat pump water heater, and the like.

  Rotary compressors are used in refrigerators and air conditioners because of their compactness and simple structure, and recently used in heat pump water heaters and the like. In addition, it has been introduced that the two-stage compression refrigeration cycle is superior from the viewpoint of cooling performance coefficient (COP = cooling capacity / compressor input) and compressor reliability. Furthermore, one two-cylinder compressor is introduced. If the compression mechanism is divided into a high-stage side and a low-stage side, a two-stage compressor (compound compressor) that performs two-stage compression by one unit can be realized, and the size and cost can be reduced (for example, non-patent) Reference 1).

In the conventional multistage rotary compressor, the rotation angle range for performing the high-stage side and low-stage side compression steps is approximately the same as long as it can be arranged in the cylinder. In a multi-stage rotary compressor in which the refrigerant compressed by the low-stage compression mechanism is guided to the high-stage compression mechanism and further compressed, the rotation angle range in which the high-stage compression mechanism performs the compression process is reduced to a low stage. It is disclosed that it is smaller than the rotation angle range of the compression mechanism on the side (see, for example, Patent Document 1).
However, this multistage rotary compressor provides the advantage that parts such as rollers can be shared between the low stage side and the high stage side, but the rotational angle range that the high stage side compression mechanism does not suck is the conventional multistage rotary compressor. Pressure pulsation occurs at the intermediate connection from the low-stage compression mechanism to the high-stage compression mechanism, resulting in compressor performance (compressor efficiency). , Noise reduction and reliability).

  Further, in the conventional two-stage rotary compressor, the two low-stage and high-stage cylinders are arranged in the same phase in a plane, and the crankshaft eccentric portion has a phase of 180 degrees (in the following description, the angle Is expressed as degrees and is the same as degree), and the compression timing on the high stage side is set to be delayed 180 degrees from the low stage side. At this time, the discharge valve is opened and the discharge is started. At this time, the high stage side has not reached the suction start angle. As described above, when the discharge timing of the low-stage compression mechanism deviates from the suction timing of the high-stage compression mechanism, pressure pulsation occurs in the intermediate connecting portion.

  Moreover, since the low stage discharge pressure (intermediate pressure) of the two-stage rotary compressor is smaller than the discharge pressure of the single stage compressor, the low stage discharge timing is early. In particular, in the case of a two-stage rotary compressor for a heat pump type water heater using a carbon dioxide refrigerant developed in recent years, the isentropic index of the carbon dioxide refrigerant is larger than that of the chlorofluorocarbon refrigerant, and the discharge timing on the low stage side is high. Since it is faster, the influence of the pressure pulsation of the intermediate connecting portion becomes larger.

Therefore, as a method of removing the pressure pulsation generated in the intermediate connecting portion, means for setting the compression timing of the high-stage compression mechanism to be advanced by about 270 degrees from that of the low-stage compression mechanism is disclosed (for example, , See Patent Document 2).
Further, in order to shorten the length of the communication path between the low-stage compression mechanism and the high-stage compression mechanism, the plane arrangement angle between the low-stage compression mechanism and the high-stage compression mechanism is shifted. This means that the gas discharged from the lower stage compression mechanism improves the followability of the gas sucked into the higher stage compression mechanism, reduces the pressure pulsation generated in the communication path, and improves the compression efficiency. It is disclosed that improvement and noise / vibration can be reduced (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 3-182893 JP-A-1-247785 JP 2003-148366 A (Japan) Refrigeration and Air Conditioning Society, “Advanced Standard Text Refrigeration and Air Conditioning Technology, Refrigeration”, Japan Refrigeration and Air Conditioning Society, July 31, 2000, p. 50-55, p. 98-101

  However, the low-stage compression mechanism and the high-stage compression mechanism are each provided with a vane, a vane storage chamber, a suction passage, a discharge passage, and an intermediate injection passage. Of the two cylinders having substantially the same positional relationship between the opening and the discharge port, the high-stage cylinder is rotationally moved in the anti-compression direction with respect to the low-stage side, so that the low-stage compression mechanism and the high-stage compression mechanism are If it is arranged to shorten the length of the communication path, there will be a problem that several bolts (usually four or more required) that pass through the low-stage cylinder and the high-stage cylinder and are fastened from above and below cannot be evenly arranged. .

  The clearance in the height direction of the rotor and vanes that move inside the cylinder is kept uniform on the order of several μm, and the cylinder height surface is sealed so that refrigerant does not leak from the compression chamber in the cylinder. If the above measures are implemented as they are to reduce the intermediate pulsation, the pressure distribution and gaps on the upper and lower surfaces of the cylinder will become non-uniform and refrigerant leakage from the compression chamber will increase, reducing the compressor efficiency. There is a fatal problem to do.

In addition, when carbon dioxide refrigerant is used, the high pressure side operates at about 10 MPa, and the pressure fluctuation in the cylinder and the differential pressure in the cylinder and the sealed container become more than three times that of the CFC refrigerant (R410A, R22, etc.). So there is a problem that it is easy to leak.
In addition, the fluctuating load applied to the bolts that fasten the low-stage cylinder and the high-stage cylinder also increases and is easy to loosen. There is a problem that it is necessary to arrange.

  An object of the present invention is to reduce pressure pulsation generated in an intermediate connecting portion that connects from a low-stage cylinder discharge port to a high-stage cylinder suction port, and penetrates the low-stage cylinder and the high-stage cylinder vertically. And providing a multistage rotary compressor in which bolts to be fastened are arranged uniformly.

  The multistage rotary compressor according to the present invention includes an annular cylinder centered on a crankshaft rotated by an electric motor, and a plurality of crankshaft eccentric portions provided eccentrically on the crankshaft. A roller that rotates eccentrically while contacting at a location, and a plurality of compression mechanisms comprising vanes that abut against the outer surface of the roller and partition the space surrounded by the inner surface of the cylinder and the outer surface of the roller into two parts, In a multistage rotary compressor in which the pressure of the refrigerant is sequentially increased by the compression mechanisms connected in series, a compression angle range in which the compression mechanism having a high pressure of the refrigerant reaching the compression process performs a compression with a low pressure of the refrigerant to be reached It is larger than the rotation angle range in which the mechanism performs the compression stroke.

  In the multistage rotary compressor according to the present invention, the rotation angle at which the low-stage discharge valve is opened on the low-stage side and the refrigerant discharge is started substantially coincides with the rotation angle at which suction is started on the high-stage side. Therefore, the pressure pulsation generated in the intermediate connecting portion is reduced, and the low-stage side cylinder and the high-stage side cylinder are fastened with the bolts arranged uniformly, so that the leakage of the refrigerant can be reduced.

Embodiment 1 FIG.
1 is a plan view of a two-stage rotary compressor according to Embodiment 1 of the present invention as viewed from above. FIG. 2 is a side view of the two-stage rotary compressor according to the first embodiment of the present invention. FIG. 3 is a longitudinal sectional view of the two-stage rotary compressor according to the first embodiment of the present invention. FIG. 4 is a longitudinal sectional view taken along another sectional line of the two-stage rotary compressor according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view as seen from the AA cross-sectional line in FIG. 6 is a cross-sectional view as seen from the BB cross-sectional line in FIG. 3 is a cross-sectional view taken along the line CC of FIG. 5, and FIG. 4 is a cross-sectional view taken along the line DD of FIG.

The CO2 refrigerant two-stage rotary compressor according to the first embodiment of the present invention includes a low-stage side compression mechanism 10, a high-stage side compression mechanism 30, and an electric motor 9 that are housed in a sealed container 8. The low-stage compression mechanism 10 is sandwiched between the low-stage discharge muffler 18 and the intermediate plate 5, and the high-stage compression mechanism 30 is sandwiched between the intermediate plate 5 and the high-stage discharge muffler 38.
Further, in the CO2 refrigerant two-stage rotary compressor, the refrigerant guided to the suction muffler 3 from the refrigerant circuit (not shown) outside the hermetic container 8 via the shell suction pipe 1 passes from the lower stage suction pipe 15 to the lower stage side. Inhaled into the compression mechanism 10.

In the CO2 refrigerant two-stage rotary compressor, the low-stage discharge pipe 16 that discharges the refrigerant compressed to the intermediate pressure by the low-stage compression mechanism 10 and the high-stage that introduces the refrigerant into the high-stage compression mechanism 30. The intermediate suction pipe 35 is connected to the lower suction pipe 35, the lower discharge pipe 16, and the higher suction pipe 35.
In the CO2 refrigerant two-stage rotary compressor, the refrigerant compressed to a high pressure by the high-stage compression mechanism 30 is discharged from the shell discharge pipe 2 to the refrigerant circuit outside the sealed container 8.
An intermediate injection pipe 49 for intermediate injection is connected in the middle of the intermediate connecting pipe 48, and the intermediate injection pipe 49 is opened and closed by an opening / closing valve 50.

The electric motor 9 includes a stator 9a fixed in the hermetic container 8 and a rotating rotor 9b provided with a rotating shaft. The crankshaft 6 is connected to the rotating shaft of the electric motor 9.
Both ends of the crankshaft 6 are rotatably supported by a short shaft side bearing 7a and a long shaft side bearing 7b.
Between the short shaft side bearing 7a and the long shaft side bearing 7b of the crankshaft 6, a low stage side crankshaft eccentric part 6a and a high stage side crankshaft eccentric part 6b which are separated by a predetermined distance are provided. The eccentric amount of the low-stage crankshaft eccentric portion 6a is larger than the eccentric amount of the high-stage crankshaft eccentric portion 6b.

Both the low stage compression mechanism 10 and the high stage compression mechanism 30 are rolling piston compression mechanisms.
As shown in FIG. 5, the low-stage compression mechanism 10 includes a low-stage roller 12 that is fitted to the low-stage crankshaft eccentric portion 6a on the inner surface, and an annular low-profile around the shaft center of the crankshaft 6. The lower cylinder 11, the lower vane 14 that contacts the outer surface of the lower roller 12, the support spring 21 that presses the lower stage vane 14 against the outer surface of the lower roller 12, the lower vane 14, and the supporting spring A vane storage chamber 22 provided in the low-stage cylinder 11 for storing 21 is provided.
A low-stage side cylinder suction port 23 is provided on the inner diameter surface of the low-stage side cylinder 11 to guide the refrigerant to the low-stage side suction chamber 13 a, and from the low-stage side suction pipe 15 connected to the sealed container 8. A low-stage suction connection flow path 24 is provided to guide the low-stage cylinder suction port 23.
Further, the low-stage discharge valve 17 attached to the low-stage discharge valve space 54 of the short shaft-side bearing 7a opens when the refrigerant in the low-stage compression chamber 13b reaches a predetermined pressure. The refrigerant is discharged from the cylinder discharge port 26 to the low-stage discharge muffler 18 through the low-stage discharge connection flow path 25 and further to the low-stage discharge connected to the sealed container 8 through the low-stage discharge connection flow path 25. It is discharged into the tube 15. Subsequently, the high-stage suction pipe 35 is connected to the high-stage compression mechanism 30.

  The low-stage vane 14 divides the low-stage cylinder inner space 13 formed between the outer surface of the low-stage roller 12 and the inner diameter surface of the low-stage cylinder 11 into two parts. One divided lower-stage cylinder inner space 13 connected with the cylinder suction port 23 is referred to as a lower-stage suction chamber 13a, and the other divided lower-stage cylinder inner space 13 is referred to as a lower-stage compression chamber 13b.

A flow path 27 that extends from the vicinity of the vane storage chamber 22 to the low-stage cylinder suction port 23 is provided on the inner diameter surface of the low-stage cylinder 11 of the low-stage compression mechanism 10.
FIG. 7 shows a flow path 27 provided from the vicinity of the vane storage chamber 22 to the low-stage cylinder suction port 23 on the inner diameter surface of the low-stage cylinder 11 according to Embodiment 1 of the present invention.
In FIG. 7A, the flow path 27 is provided by chamfering from the vicinity of the vane storage chamber 22 to the low-stage cylinder suction port 23 at the end in the height direction of the inner diameter surface of the low-stage cylinder 11.
In addition, as shown in FIG. 7B, a groove 27 is processed by an end mill (for example, a groove depth of 0.2 mm and a groove width of 1 mm) in the vicinity of the center in the height direction of the inner diameter surface of the low-stage cylinder 11. May be provided.
Further, the flow path 27 may be secured by reducing the groove depth for the entire inner diameter surface of the low-stage cylinder 11 (for example, 0.1 mm).

As shown in FIG. 6, the high-stage compression mechanism 30 includes a high-stage roller 32 that fits on the inner surface with the high-stage crankshaft eccentric portion 6 b, and an annular high center around the center of the crankshaft 6. A high-stage vane 34 that contacts the outer surface of the high-stage roller 31, a support spring 41 that presses the high-stage vane 34 against the external surface of the high-stage roller 32, a high-stage vane 34, and a support spring A vane storage chamber 42 provided in the high-stage cylinder 31 that stores 41 is provided.
A high-stage cylinder suction port 43 for guiding the refrigerant to the high-stage side suction chamber 33 a is provided on the inner diameter surface of the high-stage side cylinder 31, and the refrigerant is supplied from the low-stage side compression mechanism 10 to the high-stage side cylinder suction port. 23, a high-stage suction pipe 35 connected to the sealed container 8 and a high-stage suction connection flow path 44 formed in the high-stage cylinder 31 are provided.
The high-stage discharge valve 37 attached to the high-stage discharge valve space 55 of the long-axis bearing 7b opens when the refrigerant in the high-stage compression chamber 33b reaches a predetermined pressure. The refrigerant is discharged from the cylinder discharge port 46 into the high-stage discharge muffler 38 through the high-stage discharge connection passage 45. Then, it is guided from the shell discharge 2 to the circuit outside the sealed container 8 through the sealed container 8.

The high-stage vane 34 divides the high-stage cylinder inner space 33 between the outer surface of the high-stage roller 32 and the inner diameter surface of the high-stage cylinder 31 into two, and the high-stage cylinder suction port One of the divided high-stage cylinder inner spaces 33 connected to 43 is referred to as a high-stage suction chamber 33a, and the other divided high-stage cylinder inner space 33 is referred to as a high-stage compression chamber 33b.
The outer diameter of the low-stage roller 12 is set smaller than the outer diameter of the high-stage roller 32. By doing in this way, the volume of the low stage side cylinder inner space 13 is increased.

  As shown in FIG. 5, one of the four bolts 51 that fastens the low-stage cylinder 11 and the high-stage cylinder 31 in the vertical direction, one of which is the low-stage vane storage chamber 22 and the low-stage cylinder. Since it is arranged between the suction ports 23, the four fastening bolts 51 can be arranged evenly, and the cylinder height gap can be uniformly maintained at a level of several μm.

Next, the angles used in the description of the present invention will be described. One is a position angle used to indicate the position of a fixed member such as a cylinder. The other is a rotation angle used to indicate the position of a rotating member such as the crankshaft 6.
First, the position angle will be described.
The low-stage side compression mechanism 10 and the high-stage side compression mechanism 30 are projected on a plane perpendicular to the axis center of the crankshaft 6, and the axis center of the crankshaft 6 is used as the origin with respect to the projected image. A line passing through the low-stage vane 14 is a reference line, and an elevation angle between the reference line and a line extending from the center of the crankshaft 6 is a position angle. At this time, the direction in which the crankshaft 6 rotates in the direction in which the sucked refrigerant is compressed, that is, the counterclockwise direction in FIGS. 5 and 6 is defined as the positive direction.

  In general, the position of the high-stage vane 34 of the high-stage compression mechanism 30 is a position rotated around the shaft center of the crankshaft 6 by the position angle β, but the high-stage compression according to the first embodiment is performed. The high-stage vane 34 of the mechanism 30 is set so that the position angle β = 0 °, and the low-stage vane 14 and the high-stage vane 34 are projected onto a plane perpendicular to the axis center of the crankshaft 6. Sometimes they are placed so as to overlap.

The position angle θ _cb1 is an end angle of the low-stage side cylinder suction port 23, is an angle at which compression is started on the low-stage side, and is substantially equal to the position angle θ _S1 . The position angle θ _co1 is an angle at which discharge is started on the lower stage side, and is an angle when the pressure in the lower stage compression chamber 13b reaches an intermediate pressure. The position angle θ _ce1 is the angle at the start of the low-stage side cylinder discharge port 26, is the angle at which compression ends on the low-stage side, and is substantially equal to the position angle θ _d1 .
In the low-stage compression mechanism 10 according to the first embodiment, the position angle theta _cb1 is 140 degrees, the position angle theta _co1 is 188 degrees, the position angle theta _ce1 is 340 degrees.

The position angle θ _cb2 is an end angle of the high- _stage side cylinder suction port 43, is an angle at which compression is started on the high- _stage side, and is substantially equal to the position angle θ _S2 . The position angle θ _co2 is an angle at which discharge is started on the high stage side, and is an angle at which the pressure in the high stage side compression chamber 33b reaches a high pressure. The position angle θ _ce2 is the angle at the _start of the high- _stage cylinder discharge port 46, is the angle at which compression ends on the high- _stage side, and is substantially equal to the position angle θ _d2 .
In the high- _stage compression mechanism 30 according to the first embodiment, the position angle θ _cb2 is 20 degrees, the position angle θ _co2 is 140 degrees, and the position angle θ _ce2 is 340 degrees.

The position angle θ _S1 is an angle at which the center of the low-stage cylinder suction port 23 is disposed, and is equal to the angle ξ _S1 . The position angle θ _d1 is an angle at which the center of the low-stage cylinder discharge port 26 is disposed, and is equal to a value obtained by subtracting the angle ξ _d1 from 360 degrees.
The position angle θ _S2 is an angle at which the center of the high-stage cylinder suction port 43 is disposed, and is equal to the angle ξ _S2 . The position angle θ _d2 is an angle at which the center of the high-stage cylinder discharge port 46 is disposed, and is equal to a value obtained by subtracting the angle ξ _d2 from 360.

The angle ξ _S1 is an elevation angle between the lower stage vane 14 and the center of the lower stage suction pipe 15. The angle ξ _d1 is an elevation angle between the lower stage vane 14 and the center of the lower stage discharge pipe 16.
The angle ξ _S2 is an elevation angle between the high stage side vane 34 and the center of the high stage side suction pipe 35. The angle ξ _d2 is an elevation angle between the high stage side vane 34 and the center of the high stage side discharge connection flow path 45. In the first embodiment, the angles ξ _S1 = 130 degrees, ξ _d1 = 15 degrees, ξ _S2 = 15 degrees, and ξ _d2 = 15 degrees.

In the range of the angle ξ _S2 , loss due to expansion work by the high-stage roller 32 occurs, so that the high-stage vane storage chamber 42, the high-stage cylinder suction port 43, and the high-stage suction pipe 35 do not interfere with each other. The smaller one is preferable. Generally, it is designed at 10 to 30 degrees.
Further, when the angle ξ _d1 and the angle ξ _d2 increase, the volume that is not discharged after compression increases, and the compressor efficiency decreases due to recompression loss. Therefore, it is preferable that the angle ξ _d1 and the angle ξ _d2 are as small as possible.

Next, the rotation angle will be described.
When a line passing from the center of the crankshaft 6 to the origin and passing from the center of the crankshaft 6 to the eccentric center of the low-stage crankshaft eccentric portion 6a is on the low-stage vane 14, the rotation angle φ of the crankshaft 6 is The direction in which the crankshaft 6 rotates in the direction in which the sucked refrigerant is compressed is defined as a positive direction.
On the other hand, in the high-stage crankshaft eccentric portion 6b, the line connecting the center of the crankshaft 6 to the eccentric center of the high-stage crankshaft eccentric portion 6b is centered on the axis of the crankshaft 6. From the line passing through the eccentric center of the low-stage crankshaft eccentric portion 6a in the negative direction by the phase α. However, in the first embodiment, the phase α is set to 180 degrees, and when the rotation angle φ of the crankshaft 6 is 180 degrees, the center of the crankshaft 6 is shifted from the center of the crankshaft 6 to the eccentric crankshaft 6b. The high-stage vane 34 is positioned on an extended line extending to the eccentric center.

When the rotation angle of the crankshaft 6 reaches φ _cb1 , compression is started on the lower stage side, and φ _cb1 is equal to the position angle θ _cb1 . When the rotation angle of the crankshaft 6 becomes φ _co1 , discharge is started on the lower stage side, and φ _co1 is equal to the position angle θ _co1 . When the rotation angle of the crankshaft 6 becomes phi _ce1, it is compressed by the low stage side ends, phi _ce1 is equal to the position angle theta _ce1.
Thus, the rotation angle range of the compression stroke in the low-stage compression mechanism 10 is (φ _ce1 -φ _cb1 ), and in the first embodiment, it is 200 degrees (340 degrees-140 degrees).

When the rotation angle of the crankshaft 6 becomes _φcb2 , compression is started on the higher _stage side, and _φcb2 is equal to a value obtained by adding α = 180 degrees to the position angle _θcb2 . When the rotation angle of the crankshaft 6 becomes φ _co2 , discharge is started on the higher stage side, and φ _co2 is equal to a value obtained by adding 180 degrees to the position angle θ _co2 . When the rotation angle of the crankshaft 6 becomes _φce2 , the compression is finished on the higher _stage side, and _φce2 is equal to a value obtained by adding 180 degrees to the position angle _θce2 .
Thus, the rotation angle range of the compression stroke in the high-stage compression mechanism 30 is (φ _ce2 −φ _cb2 ), and (φ _ce2 −φ _cb2 ) = (θ _ce2 −θ _cb2 ), and therefore 320 degrees. (340 degrees-20 degrees).
As described above, in the first embodiment, the rotation angle range of the compression stroke in the high-stage compression mechanism 30 is wider than the rotation angle range in the compression stroke of the low-stage compression mechanism 10.

Next, the operation of the low stage compression mechanism 10 will be described.
When the crankshaft 6 rotates once in the positive direction, the rotation angle φ changes from 0 degrees to 360 degrees. When the rotation angle φ of the crankshaft 6 is 0 degree, the outer surface of the low-stage roller 12 (hereinafter referred to as “low”) on the extended line extending from the center of the crankshaft 6 to the eccentric center of the low-stage crankshaft eccentric part 6a. (Referred to as a stage-side dividing line) is in contact with the low-stage vane 14. On the other hand, the outer surface of the high-stage roller 32 (hereinafter referred to as a high-stage dividing line) on the extension line of the line passing from the center of the crankshaft 6 to the eccentric center of the high-stage crankshaft eccentric part 6b The side cylinder 31 is in contact with the inner surface of the position angle θ = 180 degrees.
When the crankshaft 6 rotates and the rotation angle φ reaches φ _cb1 = 140 degrees, the low-stage side is separated from the low-stage side cylinder suction port 23 by the low-stage side dividing line and the low-stage side vane 14. The in-cylinder space 13 becomes the low-stage compression chamber 13b. When the crankshaft 6 further rotates, the refrigerant in the low-stage compression chamber 13b is compressed. When the crankshaft 6 rotates and the rotation angle φ reaches φ _co1 = 188 degrees, the low-stage discharge valve 17 is opened and the refrigerant is sent to the high-stage side.
Then, when the crankshaft 6 further rotates and the rotation angle φ reaches φ _ce1 = 340 degrees, the subsequent low-stage side suction chamber 13a is connected to the low-stage side cylinder discharge port 26, and the refrigerant pressure is reduced to reduce the low-stage stage. The side discharge valve 17 is closed.

On the other hand, when the crankshaft 6 rotates and the rotation angle φ reaches φ _cb1 = 140 degrees, the crankshaft 6 is divided by the low-stage dividing line and the low-stage vane 14 and leads to the low-stage cylinder suction port 23. When the crankshaft 6 further rotates, the low-stage side cylinder inner space 13 becomes the subsequent low-stage side suction chamber 13a, and the subsequent low-stage side suction chamber 13a sucks the refrigerant from the low-stage side suction pipe 15. By repeating this, the pressure of the refrigerant can be increased from a low pressure to an intermediate pressure.

Next, the operation of the high stage compression mechanism 30 will be described.
When the rotation angle φ of the crankshaft 6 is 0 degree, the high stage side dividing line is in contact with the inner diameter surface of the high stage side cylinder 31 at the position angle θ = 180 degrees. At this time, the refrigerant pressure in the high-stage compression chamber 33b that is separated by the high-stage dividing line and the high-stage vane 34 and does not connect to the high-stage cylinder suction port 43 reaches a high pressure, and the high-stage discharge valve 37 is It is opened and the refrigerant is discharged into the sealed container 8.
When the rotation angle φ of the crankshaft 6 reaches 160 degrees, the subsequent high-stage suction chamber 33a is connected to the high-stage cylinder discharge port 46, the refrigerant pressure decreases, and the high-stage discharge valve 37 is closed.
When the rotation angle φ of the crankshaft 6 reaches 200 degrees, the high-stage cylinder inner space 33 that is divided by the high-stage dividing line and the high-stage vane 34 and is connected to the high-stage cylinder suction port 43 is formed. It becomes the high stage side suction chamber 33a. When the crankshaft 6 further rotates, the high stage suction chamber 33a sucks the refrigerant from the high stage suction pipe 35.

  On the other hand, when the crankshaft 6 rotates and the rotation angle φ reaches 200 degrees, the crankshaft 6 is separated by the high-stage dividing line and the high-stage vane 34 and separated from the high-stage cylinder suction port 43. The stage side cylinder inner space 33 becomes the high stage side compression chamber 33b. When the crankshaft 6 further rotates, the refrigerant in the higher stage compression chamber 33b is compressed. When the crankshaft 6 rotates and the rotation angle φ reaches 320 degrees, the high-stage discharge valve 37 is opened and the refrigerant is discharged into the sealed container 8. By repeating this, the pressure of the refrigerant can be increased from an intermediate pressure to a high pressure.

In the first embodiment of the present invention, the low-stage vane 14 and the high-stage vane 34 are arranged so as to overlap at a position angle θ = 0 degrees, and the low-stage vane 14 and the low-stage suction pipe 15 are arranged. angle xi] _S1 130 degrees and by the angle xi] _S2 of the high-stage vane 34 and high-stage suction pipe 35 to 15 degrees, the crank from the rotational angle phi _co1 to initiate discharge at lower stage Since the rotation angle φ _cb2 at which the high stage side starts suction is reached with only a slight rotation of the shaft 6, the discharge start timing on the low stage side and the suction start on the high stage side are the causes of the pulsation of the intermediate connecting portion. The timing deviation can be reduced.

  Further, if the low-stage side suction pipe 15 and the high-stage side suction pipe 35 are arranged at positions overlapping when projected onto a plane perpendicular to the axial center of the crankshaft 6 as in the prior art, Although the mounting position is close and difficult to handle, the high-stage suction pipe 35 is mounted at a position angle of 15 degrees as in the first embodiment, while the low-stage suction pipe 15 is mounted at a position angle of 130 degrees. Therefore, the mounting position is greatly shifted in the circumferential direction on the outer peripheral surface of the sealed container 8, so that the handling becomes easy.

  Further, since the low-stage discharge pipe 16 is attached at a position angle of 345 degrees and the high-stage suction pipe 35 is attached at a position angle of 15 degrees, the angle formed is 30 degrees apart. Is driven in the radial direction from the outside of the sealed container 8, it is easy to align the center of the crankshaft 6 with the axial center of the sealed container 8.

Next, prior to the description of the cycle variation of the CO2 refrigerant two-stage rotary compressor according to the first embodiment, the cycle variation of the conventional CO2 refrigerant two-stage rotary compressor will be described.
FIG. 8 is a graph showing the relationship between the rotation angle and internal pressure fluctuation when a conventional CO2 refrigerant two-stage rotary compressor is operated at (conditions: 60 Hz, 10.1 MPa / 4 MPa, 3.5 cc / 5 cc). FIG. 9 is a graph showing the relationship between the rotation angle and the intermediate volume when a conventional CO2 refrigerant two-stage rotary compressor is operated. FIG. 10 is a pV diagram when a conventional CO2 refrigerant two-stage rotary compressor is operated. FIG. 11 is a graph showing the relationship between the rotation angle and the volume flow rate when a conventional CO2 refrigerant two-stage rotary compressor is operated.

In the conventional CO2 refrigerant two-stage rotary compressor, the rotation angle φ _cb1 at which compression starts on the lower stage side is 20 degrees, the rotation angle φ _co1 at which refrigerant discharge is started is 140 degrees, and the refrigerant compression ends. The rotation angle φ _ce1 is 340 degrees, and the higher _stage is the same as in the first embodiment.
On the low-stage side, compression starts from the suction pressure P _S and the suction volume V _S at the rotation angle φ _cb1 , and at the rotation angle φ _co1 , the low-stage side has an intermediate volume V _m and an intermediate pressure P _m of 6.8 MPa. The discharge valve 17 is opened and refrigerant discharge is started. The intermediate volume V _m at the start of discharge was obtained from the equation (1), and the rotation angle φ _co1 was obtained from the equation (2). f (V _m ) is a function of the intermediate volume V _m .

V _m = V _S × (P _m / P _S ) ^{−1 / n} (1)
φ _co1 = f (V _m ) (2)

Here, the relationship between the rotation angle φ of the rotary compressor and the compression chamber volume V _c (corresponding to the equation (2)) is, for example, “Masayoshi Yanagisawa,“ Basic motion characteristics of a rolling piston type rotary compressor. Research ", Doctoral dissertation, Shizuoka University, 1983, p. 4-5. From this, the discharge start angle in the compressor operating condition corresponding to the ASHRAE standard was calculated. Table 1 shows the rotation angle at the start of discharge by the refrigerant type of the single-stage rotary compressor. Table 2 shows the rotation angle at the start of discharge by the refrigerant type on the lower stage side of the two-stage compressor.

  It can be seen that the carbon dioxide refrigerant has a larger isenthalpy index and reaches the discharge pressure faster than the CFC refrigerant (R22, R401A). Furthermore, it can be seen that the lower stage side of the two-stage rotary compressor arrives earlier.

From FIG. 9 and FIG. 11, suction is started at the rotation angle φ _cb2 = 200 degrees on the high stage side, but delayed by 60 degrees from the rotation angle φ _co1 = 140 degrees at which discharge is started on the low stage side. Further, the intermediate volume in one cycle is obtained from the low-stage compression chamber volume + the high-stage suction chamber volume + the low-stage discharge muffler volume + the intermediate connecting portion volume, and the change in the intermediate volume is about ± 9.7%. I understand that. As a result, a pressure pulsation of about 10% of the absolute pressure is generated in the intermediate connecting portion.
From FIG. 10, when the loss due to the pressure pulsation in the intermediate connecting portion is indicated by the hatched portion of the PV diagram, it accounts for about 4.9% of the compressor input, which is a large ratio.

  Next, the cycle fluctuation of the CO2 refrigerant two-stage rotary compressor according to the first embodiment of the present invention will be described. FIG. 12 is a graph showing the relationship between the rotation angle and the internal pressure fluctuation when the CO2 refrigerant two-stage rotary compressor according to the first embodiment of the present invention is operated. FIG. 13 is a graph showing the relationship between the rotation angle and the intermediate volume when the CO2 refrigerant two-stage rotary compressor according to Embodiment 1 of the present invention is operated. FIG. 14 is a pV diagram when the CO2 refrigerant two-stage rotary compressor according to the first embodiment of the present invention is operated. FIG. 15 is a graph showing the relationship between the rotation angle and the volume flow rate when the CO2 refrigerant two-stage rotary compressor according to Embodiment 1 of the present invention is operated.

In the first embodiment, since the low-stage angle ξ _S1 is set to 130 degrees, the rotation angle φ _cb1 at which compression starts on the low-stage side becomes 140 degrees, and the low-stage discharge valve 17 is opened. The rotation angle φ _co1 is 188 degrees. Since the rotation angle φ _cb2 at which suction starts on the high stage side is close to the rotation angle φ _co1 at which discharge starts on the low stage side, the pressure pulsation width generated at the intermediate connecting portion is about ± 2. The loss due to the pressure pulsation at the intermediate connection was reduced to about 1.9% of the compressor input. Further, it can be seen from the pV line in FIG. 14 that the loss due to pressure pulsation has become extremely small as shown by the hatched lines.

Further, the eccentric amount of the low-stage crankshaft eccentric portion 6a is made larger than the eccentric amount of the high-stage crankshaft eccentric portion 6b, and the outer diameter of the low-stage roller 12 is smaller than the outer diameter of the high-stage roller 32. As a result, the volume of the low-stage side cylinder inner space 13 is increased, so that the volume of the low-stage side compression chamber 13b, which is reduced by increasing the rotation angle φ _cb1 at which compression starts on the low-stage side, to 140 degrees, is reduced. Can keep big.

Further, the angle ξ _{S1 is set} to 130 degrees, but since the flow path 27 is provided from the vicinity of the low stage side vane 14 to the low stage side cylinder suction port 23, the low stage side vane 14 and the low stage side division are provided. The refrigerant is sucked through the flow path 27 into the low-stage cylinder inner space 13 surrounded by the line, and the low-stage roller 12 can be prevented from performing expansion work.

When the rotation angle φ _ce2 is in the range of the rotation angle φ _cb2 , the higher _stage side cannot be sucked, and therefore it is preferable that it is as small as possible within the range in which the high _stage side vane storage chamber 42 can be disposed. In the first embodiment, the angle is 40 degrees.

  In the first embodiment, the two-stage rotary compressor has been described, but the same applies to a multi-stage rotary compressor having three or more stages. In a multistage rotary compressor that gradually increases the pressure of the refrigerant from low pressure to high pressure using three or more compression mechanisms, the rotation angle range in which the compression process is performed by the high pressure side compression mechanism is set by the low pressure side compression mechanism. By making it larger than the rotation angle range in which the compression process is performed, the difference between the timing of starting discharge on the low pressure side and the timing of starting suction on the high pressure side can be reduced, and the effect of reducing the pressure pulsation of the intermediate connecting portion can be obtained.

  In the first embodiment, the case of the rolling piston type rotary compressor has been described. However, the case of the swing type other than the rolling piston type is also effective.

Embodiment 2. FIG.
In the first embodiment has been described as a rotation angle phi _cb1 = 140 degrees, since the rotation angle phi _cb1 not necessary limited to 140 degrees, in the second embodiment, the rotation angle φ _cb1 45,60,90 degrees In addition, the flow path 27 is omitted because the volume of the low-stage cylinder inner space 13 is small. Since the other parts are the same as those in the first embodiment, the same reference numerals are given to the same parts and the description thereof is omitted.
However, in actuality, the place where the low-stage side cylinder suction port 23 can be disposed may be limited in design, so that the rotation angle φ exceeds 20 degrees that has been conventionally used, and is shown in the first embodiment. A method of designing so as to be in a range of 140 degrees or less is conceivable.
Further, each stage (low stage and high stage) theoretical exclusion volume (theoretical displacement amount) V _Stth of the rotary compressor is obtained from Expression (3). However, R is a cylinder radius, r is a roller radius, and L is a cylinder length.

V _Stth = π (R ² −r ² ) L (3)

However, when the rotation angle φ _cb1 at which compression starts on the lower stage side is increased from 0 degrees, the substantially lower stage excluded volume becomes smaller than the theoretical excluded volume. When the rotation angle φ _cb1 at which compression starts on the low stage side is 70 degrees or more, the substantial low stage side excluded volume is reduced by 5% or more, and its influence cannot be ignored. For example, if the rotation angle at which compression starts on the lower stage side is 140 degrees, the theoretical excluded volume is about 67%. In such a case, it is necessary to design the cylinder so that a substantially excluded volume can be secured by increasing the cylinder radius R, decreasing the roller radius r, or increasing the cylinder length L.

Table 3 shows the low-stage discharge start rotation angle, the ratio of the intermediate pressure pulsation width when the rotation angle φ _cb1 is changed (the absolute value of the intermediate pressure is 1), and the ratio of loss due to the intermediate pulsation (all inputs). Is 1).
Thus, by setting the rotation angle φ _cb1 to 45 degrees, for example, the intermediate pressure pulsation width is improved by 2.2%, and the loss is improved by 0.9% accordingly. Furthermore, the loss due to the intermediate pulsation is improved by setting the rotation angle φ _cb1 to 60 degrees and 90 degrees.

  Conventionally, in this field, the efficiency of the compressor is improved, and the elevation angle between the cylinder suction port and the vane around the center of the crankshaft is made as small as possible. As a result of trying to bring the timing of starting discharge on the low stage side closer to the timing of starting suction on the high stage side, it is generally better to increase the elevation angle of the low stage side cylinder suction port and the low stage side vane. It was found that the efficiency could be improved by looking at it. That is, by considering the opposite of the conventional way of thinking, a remarkable effect was obtained as described above.

In particular, when carbon dioxide having a large isentropic index is used as the refrigerant, the intermediate pressure is reached when the rotation angle of the crankshaft is small on the low stage side, so that the effect of the present invention becomes more remarkable.
In addition, when the elevation angle between the low-stage side cylinder suction port and the low-stage side vane is increased in order to make the timing at which discharge starts on the low-stage side coincide with the timing at which suction starts on the high-stage side, the roller expands. It has been found that the efficiency can be improved as a whole by providing a flow path on the inner surface of the low-stage cylinder extending from the vane and the low-stage cylinder suction port so as not to perform the process.

Embodiment 3 FIG.
FIG. 16: is the top view which looked at the two-stage rotary compressor concerning Embodiment 3 of this invention from the upper direction. FIG. 17 is a side view of a two-stage rotary compressor according to Embodiment 3 of the present invention. 18 is a cross-sectional view of a two-stage rotary compressor according to Embodiment 3 of the present invention as viewed downward from a cross-sectional line similar to the AA cross-sectional line of FIG. 19 is a cross-sectional view of a two-stage rotary compressor according to Embodiment 3 of the present invention as viewed downward from a cross-sectional line similar to the BB cross-sectional line of FIG.

The CO2 refrigerant two-stage rotary compressor according to the third embodiment of the present invention is different from the CO2 refrigerant two-stage rotary compressor according to the first embodiment, in the low-stage compression mechanism 10B and the high-stage compression mechanism 30B. Since the rest is the same, the same parts are denoted by the same reference numerals and the description thereof is omitted.
As shown in FIG. 18, the low-stage compression mechanism 10B according to the third embodiment includes the low-stage compression mechanism 10, the low-stage cylinder suction port 23, and the low-stage suction connection passage 24 according to the first embodiment. The position angle at which the low-stage suction pipe 15 is arranged is different, and the other portions are the same. Therefore, the same portions are denoted by the same reference numerals, and the description thereof is omitted.
Further, as shown in FIG. 19, the high-stage compression mechanism 30B according to the third embodiment is different in the position angle between the high-stage compression mechanism 30 and the high-stage cylinder 31B according to the first embodiment. Since the other parts are the same, the same reference numerals are attached to the same parts and the description thereof is omitted.

Since the low-stage cylinder suction port 23 according to the third embodiment is provided at an angle ξ _S1 = 55 degrees of the low-stage cylinder 11, the end of the low-stage cylinder suction port 23 is positioned at the position angle θ _cb1 = The rotation angle φ _cb1 at which compression is started on the lower stage side is 60 degrees. The low-stage suction connection flow path 24 is provided at the position angle θ _S1 = 55 degrees of the sealed container 8. The low-stage suction pipe 15 is attached to the low-stage suction connection flow path 24 having a position angle θ _S1 = 55 degrees.
Then, the rotation angle φ _co1 at which the refrigerant starts to be discharged on the lower stage side is 147 degrees.

In the high-stage compression mechanism 30B according to the third embodiment, the high-stage vane 34 is provided at a position angle β = −60 degrees. The high-stage cylinder suction port 43 is provided in the high-stage cylinder 31 at the position angle θ _S2 = 360 + β + ξ _S2 . Further, the high-stage side suction port 44 is provided at the position angle θ _S2 of the sealed container 8. Further, the high stage side suction pipe 35 is attached to the high stage side suction port 44 at the position angle θ _S2 .
In the third embodiment, since β = −60 degrees and the angle ξ _S2 = 15 degrees, the position angle θ _S2 = 315 degrees, and the position angle θ _{cb2 at} the end of the high- _stage cylinder suction port 43 is 320. Degree.
As the crankshaft 6 rotates, the high-stage dividing line is delayed by 180 degrees with respect to the low-stage dividing line, so the rotation angle φ _cb2 at which the refrigerant suction starts is 140 degrees.

The high-stage cylinder discharge port 46 is provided in the high-stage cylinder 31 with a position angle θ _d2 = 360 + β−ξ _d2 , and the position angle β = −60 degrees and the angle ξ _d2 = 15 degrees. The position angle θ _d2 is 285 degrees, and the position angle θ _ce2 of the _start end of the high- _stage cylinder discharge port 46 is 280 degrees. Then, the rotation angle _φce2 at which the refrigerant discharge ends on the higher _{stage side} is 100 degrees.

  Further, a bolt 51 that fastens the low-stage cylinder 11 and the high-stage cylinder 31 from above and below passes through the low-stage cylinder 11 between the low-stage vane 14 and the low-stage cylinder intake port 23, and Since the bolts 51 can be evenly arranged, the cylinder surface pressure and the height gap can be kept uniform.

  FIG. 20 is a graph showing the relationship between the rotation angle and the internal pressure fluctuation when the CO2 refrigerant two-stage rotary compressor according to the third embodiment of the present invention is operated. FIG. 21 is a graph showing the relationship between the rotation angle and the intermediate volume when the CO2 refrigerant two-stage rotary compressor according to the third embodiment of the present invention is operated. FIG. 22 is a pV diagram when the CO2 refrigerant two-stage rotary compressor according to the third embodiment of the present invention is operated. FIG. 23 is a graph showing the relationship between the rotation angle and the volume flow rate when the CO2 refrigerant two-stage rotary compressor according to the third embodiment of the present invention is operated.

On the low-stage side, the refrigerant starts to be compressed at a rotation angle φ _cb1 = 60 degrees, and at the rotation angle φ _co1 = 147 degrees, the low-stage discharge valve 17 is opened to discharge the refrigerant to the high-stage side. On the other hand, on the high _stage side, the refrigerant suction starts at the rotation angle φ _cb2 = 140 degrees.
In this way, the pressure pulsation generated in the intermediate connecting portion could be reduced to about 2% of the absolute pressure. And the loss by pressure pulsation became small, and the ratio for the compressor input reduced to about 1%.

Thus, the high stage side crankshaft eccentric part 6b and the low stage side crankshaft eccentric part 6a are arranged so that the high stage side parting line is 180 degrees behind the low stage side parting line, and the high stage side vane 34 is By arranging at a position rotated by a position angle of −30 degrees from the lower stage vane 14, the rotation angle at which the refrigerant starts to be discharged on the lower stage side coincides with the rotation angle at which the refrigerant suction starts on the higher stage side. The pressure pulsation generated in the intermediate connecting portion can be suppressed.
Note that the position angle β is not limited to −60 degrees, and if the position angle β is within a range of less than 0 degrees and greater than −180 degrees, the same effect as in the third embodiment can be obtained.

Embodiment 4 FIG.
FIG. 24 is a longitudinal sectional view of a CO2 refrigerant two-stage rotary compressor according to the fourth embodiment of the present invention. 25 is a cross-sectional view as seen from the EE cross-sectional line in FIG. 26 is a cross-sectional view as seen from the FF cross-sectional line in FIG. 27 is a cross-sectional view as seen from the GG cross-sectional line in FIG. 24 is a cross-sectional view taken along the line HH of FIG.

  The CO2 refrigerant two-stage rotary compressor according to the fourth embodiment of the present invention connects the low-stage compression mechanism 10D and the high-stage compression mechanism 30D to the CO2 two-stage rotary compressor according to the third embodiment. The difference is that an intermediate communication part is added in the sealed container 8 and the intermediate injection pipe 49 is connected to the high-stage side cylinder suction port 43, and the other parts are the same. The description is omitted. The low-stage discharge pipe 16 and the high-stage suction pipe 35 are omitted.

In the low-stage compression mechanism 10D according to the fourth embodiment, the low-stage cylinder discharge port 26 is opened on the surface facing the high-stage compression mechanism 30B of the low-stage compression mechanism 10B according to the third embodiment. Since the surface facing the low-stage discharge muffler 18 is closed and the low-stage discharge connection flow path 25 of the sealed container 8 is omitted, and the rest is the same, the same portions are denoted by the same reference numerals and described. Is omitted.
The high-stage side compression mechanism 30D according to the fourth embodiment is such that the high-stage side cylinder suction port 43 is opened on the surface facing the low-stage side compression mechanism 10B of the high-stage side compression mechanism 30B according to the third embodiment. Since the rest is the same, the same reference numerals are attached to the same parts, and the description is omitted.

The intermediate communication portion according to the fourth embodiment forms a first intermediate plate 5a to which a low-stage discharge valve 17D connected to the low-stage cylinder discharge port 26 is attached and a low-stage discharge valve space 54 to form a high The second intermediate plate 5 b connected to the stage side suction connection flow path port 44 is provided.
Further, instead of the high-stage suction pipe 35 according to the third embodiment, an intermediate injection pipe 49 is connected to the high-stage suction connection flow path 44 at the angular position. The low-stage discharge refrigerant and the injection refrigerant are merged here, and then guided to the high-stage suction chamber 33a through the high-stage cylinder suction port.

The position angle θ _d1 of the low-stage cylinder discharge port 26 is 345 degrees, the position angle θ _S2 of the high-stage cylinder suction port 43 is 320 degrees, and the first intermediate plate 5a and the second intermediate plate 5b Are overlapped, the low-stage discharge valve space 54 and the high-stage discharge valve space 55 overlap.

Thus, the high stage side crankshaft eccentric part 6b and the low stage side crankshaft eccentric part 6a are arranged so that the high stage side parting line is 180 degrees behind the low stage side parting line, and the high stage side vane 34 is Piping outside the hermetic container 8 by rotating the position angle -30 degrees from the low stage side vane 14 and providing an intermediate communication part between the low stage side compression mechanism 10B and the high stage side compression mechanism 30B. The low stage compression mechanism 10D and the high stage compression mechanism 30D can be connected in series.
Further, the high-stage crankshaft eccentric part 6b and the low-stage crankshaft eccentric part 6a are arranged so that the high-stage dividing line is 180 degrees behind the low-stage dividing line, and the high-stage vane 34 is made low. Since the low-stage side cylinder discharge port 26 and the high-stage side cylinder suction port 43 are close to each other by being rotated by a position angle of −30 degrees from the stage-side vane 14, the loss of the intermediate coupling portion can be reduced.

Embodiment 5. FIG.
FIG. 28 is a longitudinal sectional view of a CO2 refrigerant two-stage rotary compressor according to the fifth embodiment of the present invention. 29 is a cross-sectional view as seen from the JJ cross-sectional line in FIG. 30 is a cross-sectional view as seen from the KK cross-sectional line in FIG. 28 is a cross-sectional view taken along the line LL in FIG.

The CO2 refrigerant two-stage rotary compressor according to Embodiment 5 of the present invention differs from the CO2 refrigerant two-stage rotary compressor according to Embodiment 4 in that the intermediate injection pipe 49 is connected to the second intermediate plate 5Eb. Since the rest is the same, the same parts are denoted by the same reference numerals and the description thereof is omitted.
In the second intermediate plate 5Eb according to the fifth embodiment, the injection refrigerant mixing chamber 58 and the low-stage discharge valve space 54 are formed adjacent to each other. Further, the intermediate injection pipe 49 is connected to an injection refrigerant mixing chamber 58 via an injection intermediate injection connection flow path 56.

  The refrigerant discharged from the low-stage compression chamber after the low-stage discharge valve 17D attached to the first intermediate plate 5a is opened after the pressure is increased to the intermediate pressure by the low-stage compression mechanism 10D is injected into the second intermediate plate 5Eb. After merging and mixing with the intermediate injection pipe 49 in the refrigerant mixing chamber 58, the refrigerant is sucked into the high-stage suction chamber 33a.

  Further, as in the invention shown in Japanese Patent Application No. 2005-015491, in order to introduce the low-temperature intermediate pressure refrigerant into the low-stage vane storage chamber 22, the high-stage discharge valve space 55 and the low-stage vane storage chamber 22 are flat. The intermediate pressure communication passages 57 were connected so that the general positional relationship was overlapped.

In the first to fifth embodiments described above, the case where carbon dioxide is used as the refrigerant has been described. However, even when other vapor compression cycle refrigerants such as a chlorofluorocarbon refrigerant and a hydrocarbon refrigerant are used, the same method is used. By reducing the difference between the stage-side discharge timing and the high-stage side suction timing, an appropriate performance improvement effect can be obtained.
In addition, although the phase difference between the low-stage dividing line and the high-stage dividing line is 180 degrees, the means for reducing the difference between the timing at which discharge starts on the low-stage side and the timing at which suction starts on the high-stage side has been described. Even if the phase delay of the high-stage dividing line with respect to the low-stage dividing line is less than 180 degrees, the same effect as in the first to fifth embodiments can be obtained.

  In addition, as a means for reducing the intermediate pressure pulsation width, there is a method of increasing the volume of the intermediate coupling portion, but it is not necessarily effective in reducing the loss due to the intermediate pulsation and improving the compressor efficiency. It was. For example, when the volume of the low-stage discharge muffler, which is the space immediately after discharge from the low-stage discharge valve, is increased, the intermediate pressure pulsation width and the loss due thereto are reduced, and the compressor efficiency is improved. Since the loss due to the intermediate pulsation can be reduced to a negligible level by setting the low-stage discharge muffler volume to about 10 times the low-stage exclusion volume, the same effects as in the first to fifth embodiments can be obtained. However, when the volume of the intermediate connecting portion is increased, the loss may increase. For example, if a buffer tank is connected to the intermediate connecting pipe 48 provided outside the sealed container 8 in FIG. 2, the loss due to the intermediate pressure pulsation increases, and the compressor efficiency may decrease. Moreover, if the opening degree of the valve connected to the buffer tank is appropriately adjusted based on the thermoacoustic theory, the compressor efficiency is improved.

  Further, in the above-described first to fifth embodiments, in order to form an intermediate connecting portion that connects the low-stage cylinder discharge port 26 to the high-stage cylinder suction port 43, the low-stage cylinder 11 and the intermediate plate 5 are provided. O-ring rubber (made of fluorine rubber, nitrile rubber, etc.) as a means for sealing the short bearing surface and lower lid surface of the low-stage discharge muffler and between the high-stage cylinder 31 and the intermediate plate 5, It has been found that it is not durable against critical CO2 refrigerant and cannot withstand operation for more than 100 hours. Therefore, metal gaskets, metal O-rings, metal seal rings, etc. were used.

These metal seals are a combination of an elastic base material and a surface coating material. As an elastic base material, Inconel has the most excellent resilience compared to stainless steel and piano wire.
As the surface coating material, an annealed metal material such as aluminum, silver, gold, copper, nickel, stainless steel, inconel, or indium, or a tetrafluoroethylene resin material such as PTFA or PFA was used.
In addition, an O-ring in which the rubber material for the center layer and the ethylene tetrafluoride resin material for the surface layer were combined was also effective.

It is the top view which looked at the two-stage rotary compressor concerning Embodiment 1 of this invention from upper direction. It is a side view of the two-stage rotary compressor concerning Embodiment 1 of this invention. It is a longitudinal cross-sectional view of the two-stage rotary compressor concerning Embodiment 1 of this invention. It is a longitudinal cross-sectional view in another sectional line of the two-stage rotary compressor concerning Embodiment 1 of this invention. It is sectional drawing which looked down from the AA sectional line of FIG. It is sectional drawing which looked downward from the BB sectional line of FIG. The flow path provided from the vicinity of the vane storage chamber to the low-stage cylinder suction port on the inner diameter surface of the low-stage cylinder in Embodiment 1 of the present invention is shown. It is a graph which shows the relationship between the rotation angle at the time of driving the conventional CO2 refrigerant | coolant two-stage rotary compressor, and an internal pressure fluctuation | variation. It is a graph which shows the relationship between the rotation angle at the time of driving the conventional CO2 refrigerant | coolant two-stage rotary compressor, and intermediate | middle volume. It is a pV diagram at the time of driving the conventional CO2 refrigerant two-stage rotary compressor. It is a graph which shows the relationship between the rotation angle at the time of driving the conventional CO2 refrigerant | coolant two-stage rotary compressor, and volume flow volume. It is a graph which shows the relationship between the rotation angle at the time of drive | operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 1 of this invention, and an internal pressure fluctuation | variation. It is a graph which shows the relationship between the rotation angle at the time of drive | operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 1 of this invention, and intermediate | middle volume. It is a pV diagram at the time of operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 1 of this invention. It is a graph which shows the relationship between the rotation angle at the time of driving | operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 1 of this invention, and a volume flow volume. It is the top view which looked at the two-stage rotary compressor concerning Embodiment 3 of this invention from upper direction. It is a side view of the two-stage rotary compressor concerning Embodiment 3 of this invention. It is sectional drawing which looked at the two-stage rotary compressor concerning Embodiment 3 of this invention below from the sectional line similar to the AA sectional line of FIG. It is sectional drawing which looked at the two-stage rotary compressor concerning Embodiment 3 of this invention below from the sectional line similar to the BB sectional line of FIG. It is a graph which shows the relationship between the rotation angle at the time of driving | operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 3 of this invention, and an internal pressure fluctuation | variation. It is a graph which shows the relationship between the rotation angle at the time of driving | operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 3 of this invention, and intermediate | middle volume. It is a pV diagram at the time of operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 3 of this invention. It is a graph which shows the relationship between the rotation angle at the time of driving | operating the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 3 of this invention, and a volume flow rate. It is a longitudinal cross-sectional view of the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 4 of this invention. It is sectional drawing which looked at the downward direction from the EE sectional line of FIG. It is sectional drawing which looked downward from the FF sectional line of FIG. It is sectional drawing which looked at the downward direction from the GG sectional line of FIG. It is a longitudinal cross-sectional view of the CO2 refrigerant | coolant two-stage rotary compressor concerning Embodiment 5 of this invention. It is sectional drawing which looked downward from the JJ sectional line of FIG. It is sectional drawing which looked downward from the KK sectional line of FIG.

Explanation of symbols

  1 Shell suction pipe, 2 Shell discharge pipe, 3 Suction muffler, 5 Intermediate plate, 6 Crank shaft, 6a Low stage crankshaft eccentric part, 6b High stage crankshaft eccentric part, 7a Short shaft side bearing, 7b Long shaft side Bearing, 8 Airtight container, 9 Electric motor, 9a Stator, 9b Rotor, 10 Low stage side compression mechanism, 11 Low stage side cylinder, 12 Low stage side roller, 13 Low stage side cylinder inner space, 13a Low stage side suction chamber, 13b Low-stage compression chamber, 14 Low-stage vane, 15 Low-stage suction pipe, 16 Low-stage discharge pipe, 17 Low-stage discharge valve, 18 Low-stage discharge muffler, 21, 41 Support spring, 22, 42 Vane Storage chamber, 23 Low stage side cylinder suction port, 24 Low stage side suction connection flow path, 25 Low stage side discharge connection flow path, 26 Low stage side cylinder discharge port, 27 flow path, 30 High stage side compression mechanism, 31 High Step side cylinder 32 High-stage roller, 33 High-stage cylinder space, 33a High-stage suction chamber, 33b High-stage compression chamber, 34 High-stage vane, 35 High-stage intake pipe, 37 High-stage discharge valve, 38 High Stage-side discharge muffler, 43 High-stage side cylinder suction port, 44 High-stage side suction connection flow path, 45 High-stage side discharge connection flow path, 46 High-stage side cylinder discharge port, 48 Intermediate connecting pipe, 49 Intermediate injection pipe, 50 Open / close valve, 51 bolt, 54 low-stage discharge valve space, 55 high-stage discharge valve space, 56 pipe connection flow path, 57 intermediate pressure communication path, 58 injection refrigerant mixing chamber.

Claims (6)

An annular cylinder centered on a crankshaft that is rotated by an electric motor, a roller that rotates eccentrically while contacting the inside of the cylinder at one location by a plurality of eccentric portions of the crankshaft provided eccentrically on the crankshaft, and the roller A plurality of compression mechanisms each having a vane that abuts against the outer surface of the cylinder and divides a space surrounded by the inner surface of the cylinder and the outer surface of the roller into two, and the refrigerant is sequentially supplied by the compression mechanisms connected in series. In a multistage rotary compressor that increases the pressure of
A multi-stage rotary compressor characterized in that a rotation angle range in which a compression mechanism with a high refrigerant pressure reaches a compression step is larger than a rotation angle range in which a compression mechanism with a low refrigerant pressure reaches a compression stroke. Comprising the two compression mechanisms,
The crankshaft extends from the center of the crankshaft to the cylinder suction port where the refrigerant starts to be compressed after the outer surface of the roller on the line extending through the eccentric center of the crankshaft eccentric portion contacts the vane. 2. The multistage rotary compressor according to claim 1, wherein the rotation angle is larger than that of the compression mechanism in which the pressure of the refrigerant reaching the refrigerant mechanism reaching a lower pressure is higher.   The multistage rotary compressor according to claim 2, wherein the compression mechanism having a low pressure of the refrigerant to reach has a flow path extending from the vane to the cylinder suction port on an inner diameter surface of the cylinder.   The compression mechanism having a high pressure of the reaching refrigerant has a direction opposite to the direction in which the crankshaft rotates when the vane compresses the refrigerant from the vane of the compression mechanism having a low pressure of the reaching refrigerant. The multistage rotary compressor according to claim 2 or 3, wherein the multistage rotary compressor is arranged at a position rotated about an axial center. A plurality of bolts for fastening the cylinders of the two compression mechanisms in the axial direction of the crankshaft;
In the compression mechanism in which the pressure of the reaching refrigerant is low, one or more bolts are disposed between a cylinder suction path for guiding the refrigerant from the outer diameter surface of the cylinder to the cylinder suction port and the vane storage chamber of the cylinder. The multistage rotary compressor according to any one of claims 2 to 4, wherein the multistage rotary compressor is provided.   The multistage rotary compressor according to any one of claims 1 to 5, wherein the refrigerant is a carbon dioxide refrigerant.

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