CN114174683A

CN114174683A - Multistage rotary compressor and refrigeration cycle device

Info

Publication number: CN114174683A
Application number: CN202080054296.9A
Authority: CN
Inventors: 平山卓也; 知念武士; 木村茂喜
Original assignee: Toshiba Carrier Corp
Current assignee: Toshiba Carrier Corp
Priority date: 2019-07-31
Filing date: 2020-07-02
Publication date: 2022-03-11
Anticipated expiration: 2040-07-02
Also published as: WO2021020017A1; JP7232914B2; CN114174683B; JPWO2021020017A1

Abstract

The multistage rotary compressor according to an embodiment of the present invention includes: a rotating shaft; a drive unit provided on one axial end side of the rotating shaft; and a compression unit provided on the other axial end side of the rotating shaft. The compression unit has: a low-stage compression mechanism portion that compresses the working fluid to an intermediate pressure; and a high-stage compression mechanism portion that compresses the working fluid at the intermediate pressure to a high pressure. The low-stage compression mechanism part and the high-stage compression mechanism part respectively have: a cylinder body; a roller mounted on the eccentric part of the rotating shaft; and a blade which advances and retreats relative to the roller and divides the cylinder chamber into a suction side and a compression side. The blades of each compression mechanism portion are biased toward the roller side by applying discharge pressure to the back surface. The cross-sectional area of the blade member of the blade constituting the low-stage compression mechanism portion is smaller than the cross-sectional area of the blade member of the blade constituting the high-stage compression mechanism portion.

Description

Multistage rotary compressor and refrigeration cycle device

Technical Field

Embodiments of the present invention relate to a multistage rotary compressor and a refrigeration cycle device.

The present application claims priority based on application No. 2019-141324 filed in japan on 31/7/2019, the contents of which are incorporated herein by reference.

Background

Conventionally, a multistage rotary compressor is known which compresses a working fluid in stages. For example, a multistage rotary compressor includes a low-stage compression mechanism, a high-stage compression mechanism, and a sealed casing. The low-stage compression mechanism portion compresses the low-pressure working fluid to an intermediate pressure. The high-stage compression mechanism section compresses the intermediate-pressure working fluid compressed in the low-stage compression mechanism section into a high pressure. The hermetic case accommodates the compression unit and the drive unit. The sealed shell is filled with the high-pressure working fluid discharged from the high-stage compression mechanism.

Each compression mechanism includes a vane. The vanes divide the cylinder chamber into a suction side and a compression side. The blade is urged towards the roller. The roller is mounted on an eccentric portion of the rotating shaft. The pressure inside the sealed casing acts on the back surface of the blade opposite to the front end surface (roller contact surface). The blade is urged toward the roller side by this pressure.

The same shell internal pressure acts on the low stage side and the high stage side of the back surface of the blade. The pressure below is applied to the blade tip end surface (roller contact surface). That is, a low pressure before compression acts on the lower stage side of the blade tip surface. An intermediate pressure after compression at the low stage side acts on the high stage side of the front end surface of the vane. The pressure difference between the two sides of the low-section side blade in the advancing and retreating direction is larger than that of the two sides of the high-section side blade in the advancing and retreating direction.

The suction volume on the low stage side is larger than that on the high stage side. The height of the cylinder body on the low section side is larger than that of the cylinder body on the high section side. The sectional area (pressure receiving area) of the low-stage-side blade is larger than the sectional area (pressure receiving area) of the high-stage-side blade. The pressing force of the blade is calculated by the sectional area × the pressure difference. The pressing force on the low stage side is larger than the pressing force on the high stage side.

In the compression unit in which the eccentric portion rotates, deflection is easily generated in the rotation shaft. The deflection of the rotating shaft is related to the inclination of the eccentric and the roller. This tilting causes the blade to contact one end of the roller. There are cases where an intermediate-pressure space (discharge space of the low-stage compression mechanism) is provided in a partition plate that partitions between the low-stage side and the high-stage side. In this case, the thickness of the partition plate becomes thick. If the thickness of the partition plate becomes thick, the distance between the bearings becomes large. If the distance between the bearings becomes larger, it becomes easier to generate deflection of the rotating shaft. If the blade is brought into contact with one end of the roller by providing the deflection of the rotary shaft, the following problems occur. That is, in the sliding portion between the blade and the roller, the local contact surface pressure increases, and uneven wear occurs. Uneven wear is likely to occur at the low stage side where both the cross-sectional area and the pressure difference are large. This uneven wear affects the reliability of the compressor.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6176782

Disclosure of Invention

Problems to be solved by the invention

The present invention addresses the problem of providing a multistage rotary compressor and a refrigeration cycle device that can suppress the occurrence of uneven wear in the sliding portions between the vanes and the rollers and can improve reliability.

Means for solving the problems

The multi-stage rotary compressor of the embodiment comprises: a rotating shaft; a drive unit provided on one axial end side of the rotating shaft; and a compression unit provided on the other axial end side of the rotating shaft. The compression unit has: a low-stage compression mechanism portion that compresses the working fluid to an intermediate pressure; and a high-stage compression mechanism portion that compresses the working fluid at the intermediate pressure to a high pressure. The low-stage compression mechanism part and the high-stage compression mechanism part respectively have: a cylinder body; a roller mounted on the eccentric part of the rotating shaft; and a blade which advances and retreats relative to the roller and divides the cylinder chamber into a suction side and a compression side. The blades of each compression mechanism portion are biased toward the roller side by applying discharge pressure to the back surface. The cross-sectional area of the blade member of the blade constituting the low-stage compression mechanism portion is smaller than the cross-sectional area of the blade member of the blade constituting the high-stage compression mechanism portion.

Drawings

Fig. 1 is a schematic configuration diagram of a refrigeration cycle apparatus including a sectional view of a multistage rotary compressor according to an embodiment.

Fig. 2 is a sectional view of a compression unit of the multi-stage rotary compressor according to the embodiment.

Fig. 3 is a sectional view III-III of fig. 2.

Detailed Description

Hereinafter, a multistage rotary compressor and a refrigeration cycle apparatus according to an embodiment will be described with reference to the drawings.

First, a refrigeration cycle apparatus will be described.

Fig. 1 is a schematic configuration diagram of a refrigeration cycle apparatus including a sectional view of a multistage rotary compressor according to an embodiment. The refrigeration cycle apparatus 1 of the present embodiment includes a multistage rotary compressor 2, a radiator 3, an expansion device (expansion valve) 4, and an evaporator (heat absorber) 5. The multistage rotary compressor 2 has a compressor main body 11 and an accumulator (gas-liquid separator) 12. The multistage rotary compressor 2 compresses a gas refrigerant as a working fluid. The radiator 3 is connected to the discharge portion 15 of the compressor body 11. The radiator 3 cools the high-temperature and high-pressure gas refrigerant discharged from the compressor body 11. The expansion device 4 is connected to the downstream side of the radiator 3. The expansion device 4 decompresses the refrigerant. The evaporator 5 is connected between the expansion device 4 and the introduction portion 12a of the accumulator 12. The evaporator 5 evaporates the refrigerant. In the figure, reference numeral 13 denotes an introduction passage extending from the discharge portion 15 of the compressor main body 11 to the introduction portion 12a of the accumulator 12.

The lead-out portion 12b of the accumulator 12 and the suction portion 14 of the compressor main body 11 are connected by the suction pipe 6. The gas refrigerant separated into gas and liquid in the accumulator 12 is guided through the suction pipe 6. The gas refrigerant is guided to the low-stage compression mechanism portion 37 of the compressor main body 11.

The refrigeration cycle device 1 shown in fig. 1 has an intermediate pressure passage 7. The intermediate-pressure passage 7 guides the intermediate-pressure gas refrigerant to the intercooler 7 a. The gas refrigerant is compressed by the low-stage compression mechanism 37 of the compressor main body 11 to have the intermediate pressure. The intermediate-pressure passage 7 guides the intermediate-pressure gas refrigerant to the high-stage compression mechanism portion 38 of the compressor main body 11. The intermediate pressure passage 7 extends from the second discharge portion 15a communicating with the low-stage compression mechanism portion 37. The intermediate pressure passage 7 extends to the second suction portion 14a communicating with the high-stage compression mechanism portion 38.

The refrigeration cycle apparatus 1 includes a second accumulator (gas-liquid separator) 8 and a second expansion device (expansion valve) 9 between the expansion device 4 and the evaporator 5. A bypass passage 8a is provided between the second accumulator 8 and the second suction portion 14a of the high-stage compression mechanism portion 38 of the compressor main body 11. The bypass passage 8a guides the gas refrigerant, which has been gas-liquid separated in the second accumulator 8, to the high-stage compression mechanism portion 38. The bypass passages 8a in fig. 1 join at a midpoint of the intermediate pressure passage 7.

The pressure of the gas refrigerant that has been gas-liquid separated in the second accumulator 8 is set as follows. The pressure of the gas refrigerant is set to be equal to the intermediate pressure of the gas refrigerant compressed in the low-stage compression mechanism portion 37 of the compressor main body 11. The multistage rotary compressor 2 may be configured without the intermediate pressure passage 7, the bypass passage 8a, the second accumulator 8, and the second expansion device 9.

The multistage rotary compressor 2 is a so-called rotary compressor. The multistage rotary compressor 2 compresses a low-pressure gas refrigerant taken into the interior thereof in two stages to obtain a high-temperature high-pressure gas refrigerant. The specific configuration of the multistage rotary compressor 2 will be described later.

The refrigerant as the working fluid circulates through the refrigeration cycle apparatus 1 while being phase-changed into a gas refrigerant and a liquid refrigerant. The refrigerant absorbs heat during the phase change from liquid refrigerant to gaseous refrigerant. The heat absorption is utilized for cooling, refrigeration, and the like. For example, HFC-based refrigeration such as R410A and R32 can be used as the refrigerantAgent, HFO-based refrigerant such as R1234yf or R1234ze, and CO₂And natural refrigerants, etc.

The radiator 3 radiates heat from the high-temperature, high-pressure gas refrigerant sent from the multistage rotary compressor 2.

The expansion device 4 reduces the pressure of the high-pressure refrigerant sent from the radiator 3 to form a low-temperature low-pressure liquid refrigerant.

The evaporator 5 vaporizes the low-temperature, low-pressure liquid refrigerant sent from the expansion device 4 to form a low-pressure gas refrigerant. The evaporator 5 takes vaporization heat from the surroundings when the low-pressure liquid refrigerant vaporizes, and cools the surroundings. The low-pressure gas refrigerant having passed through the evaporator 5 is taken into the multi-stage rotary compressor 2.

In the refrigeration cycle apparatus 1, the intermediate-pressure gas refrigerant that has been gas-liquid separated in the second accumulator 8 is guided as follows. The intermediate-pressure gas refrigerant is guided into the high-stage compression mechanism 38 of the compressor main body 11 through the bypass passage 8 a. This improves the compression performance of the compressor body 11.

Next, the multistage rotary compressor 2 will be described.

As shown in fig. 1, the multistage rotary compressor 2 of the present embodiment includes a compressor main body 11 and an accumulator 12.

The accumulator 12 is a so-called gas-liquid separator. The accumulator 12 is provided between the evaporator 5 and the compressor main body 11. The accumulator 12 is connected to the compressor main body 11 through the suction pipe 6. The accumulator 12 separates the gas refrigerant vaporized in the evaporator 5 from the liquid refrigerant that is not vaporized in the evaporator 5. The accumulator 12 supplies only the separated gas refrigerant to the compressor main body 11.

The compressor body 11 includes a rotary shaft 31, an electric motor (drive unit) 32, a compression unit 33, and a sealed casing 34 that houses the rotary shaft 31, the electric motor 32, and the compression unit 33. The compressor body 11 is disposed such that the axial direction of the rotary shaft 31 and the hermetic case 34 is the vertical direction. The rotary shaft 31 has a rotation center axis C coincident with a center axis of the hermetic case 34. In the following description, a direction along the central axis C of the rotary shaft 31 and the sealed housing 34 is referred to as an axial direction, a direction perpendicular to the axial direction is referred to as a radial direction, and a direction around the central axis C is referred to as a circumferential direction.

The sealed case 34 seals both axial ends of the cylindrical body to form a sealed container. In the closed casing 34, the electric motor 32 is housed on the upper side, and the compression unit 33 is housed on the lower side. The electric motor 32 and the compression unit 33 are coupled via the rotating shaft 31. In the sealed case 34, an electric motor 32 is provided on one end side of the rotating shaft 31, and a compression unit 33 is provided on the other end side of the rotating shaft 31. A frame 34a is provided between the electric motor 32 and the compression unit 33 in the sealed case 34. The frame 34a is annular and coaxial with the cylinder of the hermetic case 34. The frame 34a is fixed to an inner wall surface of the hermetic case 34.

A lubricant J for lubricating the compression unit 33 is stored in the bottom of the hermetic case 34. The bottom of the closed casing 34 constitutes a lubricant oil reservoir 34b in which the lubricant oil J is stored. A part of the compression element 33 is impregnated in the lubricating oil J. The high-pressure gas refrigerant compressed in the high-stage compression mechanism 38 is discharged to a space inside the sealed casing 34.

The electric motor 32 is a so-called inner rotor type DC brushless motor. The electric motor 32 is an electric motor including a stator 35 and a rotor 36. The stator 35 is fixed to an inner wall surface of an upper portion of the hermetic case 34. The rotor 36 is disposed inside the stator 35 with a radial gap. The rotor 36 is fixed to an upper portion of the rotary shaft 31.

Fig. 2 is a sectional view of the compression unit 33 of the multistage rotary compressor 2. Fig. 3 is a sectional view III-III of fig. 2.

As shown in fig. 2 and 3, the compression unit 33 is a multi-cylinder compression unit having a plurality of

cylinders

37a and 38 a. The compression unit 33 is, for example, a two-cylinder (multi-cylinder) compression unit. The compression unit 33 has a pair of (a plurality of)

cylinders

37a, 38a arranged in the vertical direction (axial direction). The compression unit 33 of the present embodiment includes a low-stage compression mechanism 37, a high-stage compression mechanism 38, and a partition plate 39. The low stage compression mechanism portion 37 is located on the axially upper side. The high stage compression mechanism portion 38 is located on the axially lower side. The partition plate 39 partitions the space between the low-stage compression mechanism portion 37 and the high-stage compression mechanism portion 38 in the vertical direction (axial direction). The low-stage compression mechanism portion 37 sucks low-pressure working fluid from the accumulator 12. The "low pressure" means a relatively low pressure with respect to the "intermediate pressure" and the "high pressure" described later. The low-stage compression mechanism portion 37 compresses (boosts) the low-pressure working fluid drawn from the accumulator 12 to a relatively high "intermediate pressure". The high-stage compression mechanism portion 38 compresses (boosts) the working fluid of the "intermediate pressure" compressed in the low-stage compression mechanism portion 37 to a relatively high "high pressure".

The low-stage compression mechanism 37 includes a low-stage side cylinder 37 a. The low-stage side cylinder 37a is provided axially parallel to the rotary shaft 31. The lower cylinder 37a is vertically penetrated by the rotary shaft 31. The low-stage side cylinder block 37a forms a circular low-stage side cylinder block hole 37 b. The low-stage side cylinder bore 37b aligns the rotation center axis C of the rotary shaft 31 with the center axis. The low-stage compression mechanism 37 includes a first bearing 41 on an upper side (opposite side to the partition plate 39 in the axial direction) of the low-stage cylinder 37 a. The first bearing 41 closes the upper end opening of the lower stage side cylinder bore 37 b. The first bearing 41 rotatably supports the first main shaft 31a above the rotary shaft 31.

The high-stage compression mechanism 38 includes a high-stage side cylinder 38 a. The high-stage side cylinder 38a is provided axially parallel to the rotary shaft 31. The high-stage cylinder 38a is vertically penetrated by the rotary shaft 31. The high stage side cylinder block 38a forms a circular high stage side cylinder block hole 38 b. The high-stage side cylinder bore 38b aligns the rotation center axis C of the rotary shaft 31 with the center axis. The high-stage side cylinder bore 38b and the low-stage side cylinder bore 37b are arranged coaxially with each other. The high-stage side cylinder hole 38b and the low-stage side cylinder hole 37b are arranged coaxially with the rotary shaft 31. The high-stage compression mechanism 38 includes a second bearing 42 below the high-stage cylinder block 38a (on the opposite side of the partition plate 39 in the axial direction). The second bearing 42 closes the lower end opening of the high-stage side cylinder bore 38 b. The second bearing 42 rotatably supports the third main shaft 31e below the rotary shaft 31.

The outer peripheral portion of the low-stage side cylinder 37a is fixed to the frame 34a in a state of being in contact with the lower surface of the frame 34 a. The outer peripheral portion of the lower cylinder 37a is fastened and fixed to the frame 34a by a bolt B1 inserted from below. A first bearing 41 is disposed on the inner peripheral side of the frame 34 a. The first bearing 41 is fixed to the low-stage side cylinder 37a in a state of being in contact with the upper surface of the low-stage side cylinder 37 a. The first bearing 41 is fastened and fixed to the lower cylinder block 37a by a bolt B2 inserted from above. The bolt B2 penetrates the lower cylinder 37a and extends downward. The bolt B2 penetrates the partition plate 39 and the high-stage side cylinder block 38 a. The bolt B2 is screwed into the threaded hole of the second bearing 42 and tightened. The first bearing 41, the low-stage side cylinder 37a, the partition plate 39, the high-stage side cylinder 38a, and the second bearing 42 are integrally fastened in a stacked state. A stacked body of the first bearing 41, the low stage side cylinder 37a, the partition plate 39, the high stage side cylinder 38a, and the second bearing 42 is fixed to the frame 34 a. The rotation shaft 31 is rotatably supported by a first bearing 41 and a second bearing 42. The first bearing 41 and the second bearing 42 are fixed to the frame 34a and further to the hermetic case 34.

The upper end opening of the low-stage side cylinder bore 37b of the low-stage side cylinder 37a is closed by the first bearing 41. The lower end opening of the lower-stage side cylinder bore 37b of the lower-stage side cylinder 37a is closed by a partition plate 39. The space defined by the low-stage cylinder 37a, the first bearing 41, and the partition plate 39 is defined as a low-stage cylinder chamber 37 c.

The lower end opening of the high-stage side cylinder bore 38b of the high-stage side cylinder block 38a is closed by a second bearing 42. The upper end opening of the high-stage side cylinder bore 38b of the high-stage side cylinder block 38a is closed by a partition plate 39. The space partitioned by the high-stage-side cylinder block 38a, the second bearing 42, and the partition plate 39 is defined as a high-stage-side cylinder block chamber 38 c.

The low-stage side cylinder block 37a and the high-stage side cylinder block 38a are axially opposed to each other with a partition plate 39 interposed therebetween. The specific structure of the partition plate 39 will be described later.

The rotary shaft 31 includes a low-stage eccentric portion 31b at a position located in the low-stage cylinder chamber 37 c. The low-stage-side eccentric portion 31b is eccentric to the radial direction side with respect to the center axis C. The rotary shaft 31 includes a high-stage eccentric portion 31d at a position located in the high-stage cylinder block chamber 38 c. The high-stage-side eccentric portion 31d is eccentric to the other side in the radial direction with respect to the center axis C.

The rotary shaft 31 includes a main shaft extending about the central axis C. The spindles include a first spindle 31a, a second spindle 31c, and a third spindle 31 e. The first main shaft 31a extends above the lower-stage eccentric portion 31 b. The second main shaft 31c extends between the low-stage-side eccentric portion 31b and the high-stage-side eccentric portion 31 d. The third main shaft 31e extends below the high-stage eccentric portion 31 d. The first main shaft 31a extends to be longer in the axial direction than the other

main shafts

31c and 31e and to be larger upward. A rotor 36 of the electric motor 32 is fixed to the first main shaft 31 a.

The

eccentric portions

31b and 31d are cylindrical with the same diameter. The

eccentric portions

31b and 31d are arranged to have a phase difference of 180 ° in the circumferential direction from each other. The

eccentric portions

31b and 31d are set to have the same eccentric amount with respect to the center axis C.

A cylindrical low-stage-side roller 45 is rotatably externally fitted to the low-stage-side eccentric portion 31 b. The low-stage-side roller 45 rotates around the center axis of the low-stage-side eccentric portion 31 b.

A cylindrical high-stage side roller 46 is rotatably externally fitted to the high-stage side eccentric portion 31 d. The high-stage-side roller 46 rotates around the center axis of the high-stage-side eccentric portion 31 d.

The first bearing 41 includes a cylindrical tube portion 41a and a flange portion 41 b. The cylindrical portion 41a is rotatably inserted through the first main shaft 31a supporting the rotating shaft 31. The flange portion 41b is formed to have a diameter enlarged on the outer peripheral side of the lower end portion of the cylindrical portion 41 a. The first muffler 43 is fixed to the first bearing 41 by, for example, the bolt B2.

The second bearing 42 includes a cylindrical tube portion 42a and a flange portion 42 b. The cylindrical portion 42a rotatably inserts and supports the third main shaft 31e of the rotating shaft 31. The flange 42b is formed to have a diameter enlarged on the outer peripheral side of the upper end of the tube 42 a. A second muffler 44 is fixed to the second bearing 42.

In the first bearing 41 and the second bearing 42, axial lengths of sliding portions with the rotary shaft 31 are denoted by reference numerals L1, L2. The sliding-section length L1 of the first bearing 41 is longer than the sliding-section length L2 of the second bearing 42. Since the sliding portion length L1 is long, the deflection of the rotating shaft 31 on the first bearing 41 side becomes small. Since the sliding portion length L1 is long, the inclination of the low-step-side eccentric portion 31b and the low-step-side roller 45 becomes small.

The eccentric portion 31b of the low-stage compression mechanism 37 is disposed in the low-stage side cylinder chamber 37c as follows. The eccentric portion 31b is disposed offset toward the first bearing 41 in the axial direction. In the low-stage compression mechanism portion 37, the axial center position of the eccentric sliding portion (the sliding portion of the eccentric portion 31b and the roller 45) is denoted by reference numeral cp 1. In the low stage compression mechanism portion 37, the axial center position of the low stage side cylinder block 37a is denoted by reference numeral cp 2. The axial center position cp1 is arranged axially closer to the first bearing 41 than the axial center position cp 2. With this arrangement, the deflection of the rotating shaft 31 on the first bearing 41 side is also reduced.

The low-stage compression mechanism 37 includes the vane (low-stage-side vane) 18. The vane 18 divides the low-stage side cylinder chamber 37c into the suction chamber 16 and the compression chamber 17. The vane 18 is held in a vane groove 18c formed in the lower cylinder 37 a. The vane 18 can move forward and backward relative to the cylinder chamber 37 c. The blade 18 brings a leading end surface (roller contact surface) 18a on the roller 45 side into contact with the outer peripheral surface of the roller 45. The vane 18 maintains the state in which the distal end surface 18a is in contact with the outer peripheral surface of the roller 45. The vane 18 and the roller 45 divide the interior of the cylinder chamber 37c into a suction chamber 16 and a compression chamber 17.

The vane 18 of the low stage compression mechanism 37 is composed of a plurality of vane members (low stage side vane members) 19a and 19 b. For example, the plurality of

blade members

19a and 19b are provided as a pair of upper and lower members so as to overlap in the axial direction. Hereinafter, only the upper and

lower blade members

19a and 19b may be referred to as the blade member 19.

The blade 18 (blade member 19) is urged toward the roller 45. The vane 18 has a back surface 18b opposite to the front end surface 18a in the radial direction (forward/backward direction) of the cylinder chamber 37 c. The vane 18 receives a casing internal pressure (pressure of the gas refrigerant in the sealed casing 34, the same applies hereinafter) on the back surface 18 b. The blade 18 is biased toward the roller 45 only by receiving the housing internal pressure at the back surface 18 b. A biasing member such as a spring is provided on the back surface 18b side of the blade 18. For example, the tip end surface 18a of the blade 18 has an arc shape as viewed in the axial direction. The front end surface 18a of the blade 18 is subjected to surface curing such as DLC (Diamond like Carbon) coating. For example, the back surface 18b of the blade 18 is flat and perpendicular to the forward/backward direction when viewed in the axial direction. In the figure, reference numeral 34c denotes a housing inner communication portion which the back surface 18b of the blade 18 faces. The case internal pressure acts by the case internal communication portion 34c communicating with the inside of the sealed case 34.

The vane 18 (the pair of

vane members

19a and 19b) is slidably (slide) held in the vane groove 18 c. The pair of

blade members

19a and 19b are slidable (retractable) in the radial direction with respect to the blade groove 18 c.

The vane 18 is biased by the pressure of the high-pressure gas refrigerant (casing internal pressure) in the sealed casing 34. The blade 18 is biased radially inward (toward the roller 45). The blade 18 has a distal end surface 18a in contact with the outer peripheral surface of the roller 45. The vane 18 maintains the state in which the distal end surface 18a is in contact with the outer peripheral surface of the roller 45. The vane 18 is eccentrically rotated by the roller 45 to advance and retreat in the radial direction.

The low-stage compression mechanism 37 performs a compression operation of the gas refrigerant by the eccentric rotation operation of the roller 45 and the forward and backward movement operation of the vane 18. The low-stage compression mechanism 37 performs a compression operation of the gas refrigerant in the low-pressure side cylinder chamber 37 c.

A suction hole 18d is formed in a part of the lower stage side cylinder block 37a in the circumferential direction. The suction hole 18d penetrates the lower stage side cylinder 37a in the radial direction. The suction holes 18d are arranged in the following manner in the eccentric rotation direction of the roller 45 (in some cases, the direction of arrow F in fig. 3 and the rotation direction of the rotary shaft 31). The suction port 18d is disposed downstream of the vane groove 18c (leftward of the vane groove 18c in fig. 3). A suction pipe 6 extending from the reservoir 12 is connected to the radially outer side of the suction hole 18 d.

Referring to fig. 2, the high-stage compression mechanism 38 includes the vane (high-stage-side vane) 21 in the same manner as the low-stage compression mechanism 37. The vane 21 divides the cylinder chamber 38c into the suction chamber 16 and the compression chamber 17. The vane 21 of the high-stage compression mechanism portion 38 is constituted by one vane member (high-stage-side vane member) 22. In the figure, the front end surfaces of the blades 21 are denoted by reference numerals 21a, and the rear surfaces of the blades 21 are denoted by reference numerals 21b, respectively. The same illustration as in fig. 3 of the high-stage compression mechanism 38 is omitted.

The blade member 22 is biased toward the roller 46 by receiving the housing internal pressure at the back surface 21 b. The blade member 22 is also biased toward the roller 46 by a biasing spring 23 (e.g., coil spring) compressed on the back surface 21b side. That is, the high-stage compression mechanism 38 includes the biasing spring 23 that biases the vane member 22. The high-stage compression mechanism 38 performs the following operations at the time of starting the multistage rotary compressor 2. The high-stage compression mechanism 38 also biases the vane member 22 toward the roller 46 in a state where the internal pressure of the casing is low. The high-stage compression mechanism 38 can compress and boost the refrigerant sucked in even in a state where the internal pressure of the casing is low.

The operation of the blade 21 formed of one blade member 22 will be described. The blade member 22 of the blade 21 receives the casing internal pressure at the back surface 21b over the entire axial direction and is biased toward the roller 46 side. The operation of the blade 18 including the plurality of blade members 19 will be described. Each blade member 19 of the blade 18 is biased by the casing internal pressure on the back surface 18b of a part (half) of the blade 18 in the axial direction.

The back surfaces of the blade members 19 and 22 are slidably held by the

cylinders

37a and 38 a. The cross-sectional area of the back surface side of each blade member 19, 22 will be described below. The cross-sectional area is a cross-sectional area obtained by cutting each blade member 19, 22 with an intersecting surface orthogonal to the advancing/retreating direction. The average one of the cross-sectional areas of the plurality of blade members 19 is smaller than the one of the cross-sectional areas of the one blade member 22.

The biasing force that each blade member 19, 22 receives from the casing internal pressure is calculated by multiplying the casing internal pressure by the cross-sectional area of each blade member 19, 22. The biasing force of each of the divided blade members 19 from the housing internal pressure is smaller than the biasing force of the integrated blade member 22 from the housing internal pressure. The biasing force of each blade member 19 of the low stage compression mechanism portion 37 from the housing internal pressure is smaller than the biasing force of the integrated blade member 22 of the high stage compression mechanism portion 38 from the housing internal pressure.

The number of blade members 19 of the low stage compression mechanism portion 37 is larger than the number of blade members 22 of the high stage compression mechanism portion 38. The number of blade members 19 of the low-stage compression mechanism portion 37 is not limited to two. For example, the number of blade members 19 of the low-stage compression mechanism portion 37 may be three or more.

The number of the blade members 22 of the high-stage compression mechanism portion 38 is not limited to one. For example, the number of the blade members 22 of the high-stage compression mechanism portion 38 may be plural. The blade member 22 of the high-stage compression mechanism portion 38 may be divided into a plurality of parts. The number of the blade members 22 of the high-stage compression mechanism portion 38 is smaller than the number of the blade members 19 of the low-stage compression mechanism portion 37.

The blade members 19 and 22 of the low-stage compression mechanism portion 37 and the high-stage compression mechanism portion 38 are not limited to the axially divided configuration. The blade members 19 and 22 of the low-stage compression mechanism portion 37 and the high-stage compression mechanism portion 38 may be divided in the circumferential direction.

The

blades

18 and 21 of the low-stage compression mechanism 37 and the high-stage compression mechanism 38 are each composed of at least one blade member 19 and 22. The cross-sectional area of each blade member 19, 22 cut by the intersecting surface perpendicular to the advancing/retreating direction will be described below. The cross-sectional area of the average one of the low-stage side blade members 19 is smaller than the cross-sectional area of the average one of the high-stage side blade members 19. The roller pressing force of the low-stage blade members 22 is suppressed to be lower than the roller pressing force of the high-stage blade members 19.

The

compression mechanism portions

37 and 38 perform the following functions by eccentric rotation of the

rollers

45 and 46. Each of the

compression mechanism portions

37 and 38 performs a suction operation of sucking the gas refrigerant into the suction chamber 16 and a compression operation of compressing the gas refrigerant in the compression chamber 17.

In the low-stage compression mechanism 37, the low-pressure gas refrigerant is sucked from the accumulator 12 by the suction operation. In the low-stage compression mechanism 37, the gas refrigerant sucked in is compressed by the compression operation and is boosted to an intermediate pressure. The gas refrigerant pressurized in the low-stage compression mechanism 37 is discharged into the intermediate pressure chamber 39c of the partition plate 39. The gas refrigerant pressurized in the low-stage compression mechanism 37 is discharged to the intermediate pressure chamber 39c through the discharge hole 47 a. The discharge hole 47a is provided in the partition plate 39.

In the high-stage compression mechanism 38, the intermediate-pressure gas refrigerant is sucked from the intermediate pressure chamber 39c by the suction operation. In the high-stage compression mechanism 38, the gas refrigerant sucked in is further compressed by the compression operation and is boosted to a high pressure. The gas refrigerant pressurized in the high-stage compression mechanism 38 is discharged to the outside of the cylinder chamber 38c (into the sealed casing 34). The gas refrigerant pressurized in the high-stage compression mechanism 38 is discharged into the hermetic casing 34 through the discharge hole 49 a. The discharge hole 49a is provided in the flange portion 42b of the second bearing 42.

The partition plate 39 is formed in a ring shape centered on the axis C. The partition plate 39 is axially divided into a plurality of (a pair of upper and lower

partition plate members

39a, 39b in the embodiment). Each

partition member

39a, 39b has a concave cross-sectional shape with the other side thereof recessed. Each of the

partition members

39a and 39b has the above-described concave cross-sectional shape and extends annularly. The

partition members

39a and 39b are coupled to each other in a state where the open side of the concave cross-sectional shape faces the other side. An intermediate pressure space (intermediate pressure chamber) 39c is formed inside the partition plate 39 by the above-described concave sectional shape. The partition plate 39 is divided into a pair of

partition plate members

39a and 39b, whereby the intermediate pressure space 39c is easily formed. By dividing the partition plate 39 into a pair of

partition plate members

39a, 39b, a later-described discharge valve device 47 can be easily provided in the partition plate 39.

By providing the intermediate-pressure space 39c in the partition plate 39, the volume of the intermediate-pressure space 39c is ensured. By securing the volume of the intermediate-pressure space 39c, the discharge pulsation of the gas refrigerant from the low-stage compression mechanism 37 is suppressed. By securing the volume of the intermediate-pressure space 39c, the suction pulsation of the gas refrigerant into the high-stage compression mechanism portion 38 is suppressed.

A discharge valve device 47 is provided on an end surface of the partition plate 39 on the low-stage compression mechanism portion 37 side. The discharge valve device 47 can discharge the intermediate-pressure gas refrigerant compressed in the low-stage compression mechanism 37 into the intermediate-pressure space 39 c.

The intermediate-pressure gas refrigerant discharged from the low-stage compression mechanism 37 into the intermediate-pressure space 39c is guided to the second suction portion 14 a. The second suction portion 14a communicates with the high-stage compression mechanism portion 38 via the intermediate-pressure passage 7. The intermediate-pressure gas refrigerant guided through the intermediate-pressure passage 7 is cooled in the intercooler 7a in the middle of the intermediate-pressure passage 7. The cooled intermediate-pressure gas refrigerant is guided to the high-stage compression mechanism portion 38. The intermediate-pressure gas refrigerant that has been gas-liquid separated in the second accumulator 8 is guided to the high-stage compression mechanism 38 through the bypass passage 8 a. The bypass passages 8a merge at a middle portion of the intermediate pressure passage 7. The intermediate-pressure gas refrigerant guided to the second suction portion 14a is compressed in the high-stage compression mechanism portion 38.

In the multistage rotary compressor 2, the gas refrigerant compressed in the low-stage compression mechanism 37 has a predetermined intermediate pressure. If the gas refrigerant becomes an intermediate pressure in the low-stage compression mechanism 37, the discharge valve device 47 of the partition plate 39 opens. When the discharge valve device 47 of the partition plate 39 is opened, the intermediate-pressure gas refrigerant is discharged into the intermediate-pressure space 39 c. The gas refrigerant is guided into the cylinder chamber 38c of the high-stage compression mechanism portion 38. The intermediate-pressure gas refrigerant introduced into the cylinder chamber 38c is compressed to a high pressure by the compression operation of the high-stage compression mechanism 38.

A high-stage side discharge valve device 49 is provided in the flange portion 42b of the second bearing 42. The high-stage side discharge valve device 49 can discharge the high-pressure gas refrigerant compressed in the high-stage compression mechanism portion 38 to the outside of the cylinder chamber 38 c.

The high-stage compression mechanism 38 compresses the gas refrigerant to a predetermined high pressure. If the gas refrigerant becomes high-pressure in the high-stage compression mechanism 38, the high-stage discharge valve device 49 of the second bearing 42 opens. When the high-stage-side discharge valve device 49 is opened, the high-pressure gas refrigerant is discharged to the outside of the cylinder chamber 38 c. The gas refrigerant is discharged into the space (second muffler chamber 44a) inside the second muffler 44. Thereafter, the gas refrigerant is appropriately discharged into the hermetic case 34.

The high-pressure gas refrigerant discharged into the second muffler chamber 44a passes through the discharge passage 33a in the compression unit 33. The gas refrigerant reaches the space (first muffler chamber 43a) in the first muffler 43. For example, the discharge passage 33a is formed so as to axially penetrate the outer peripheral sides of the second bearing 42, the low-stage side cylinder block 37a, the partition plate 39, the high-stage side cylinder block 38a, and the first bearing 41. The gas refrigerant that has reached the first muffler chamber 43a is discharged into the hermetic shell 34 through a discharge hole provided in the first muffler 43 as appropriate.

The lower end portion of the rotating shaft 31 is immersed in the lubricating oil J stored in the bottom portion of the hermetic case 34. The lower end portion of the rotating shaft 31 is immersed in the lubricating oil J together with the second muffler 44.

An oil supply path is formed in the rotary shaft 31. The oil supply path supplies the lubricating oil J to each sliding portion in the compression unit 33. The sliding portions of the compression unit 33 refer to the space between the

eccentric portions

31b, 31d and the

rollers

45, 46, the space between the rotary shaft 31 and the

bearings

41, 42, the space between the

rollers

45, 46 and the

vanes

18, 21, and the like.

The oil supply path of the rotary shaft 31 includes an axial flow passage 95, a first radial flow passage 96, and a second radial flow passage 97. The axial flow passage 95 extends coaxially with the axis C. The first radial flow passage 96 and the second radial flow passage 97 extend radially from the axial flow passage 95.

The lower end of the axial flow passage 95 opens downward at the lower end of the rotary shaft 31. The upper end of the axial flow passage 95 terminates in the first main shaft 31a above the lower stage side cylinder 37 a. The lubricating oil J in the sealed casing 34 can flow into the axial flow passage 95.

A first radial flow passage 96 is formed at a connecting portion of the first main portion 88 and the eccentric portion 31b in the rotary shaft 31. The radially inner end of the first radial flow passage 96 is open into the axial flow passage 95. The radially outer end of the first radial flow passage 96 is open radially outward on the outer circumferential surface of the rotary shaft 31 (in the oil groove extending in the circumferential direction in the drawing).

The second radial flow passage 97 is formed at a connecting portion of the third main shaft 31e and the eccentric portion 31d in the rotary shaft 31. The radially inner end of the second radial flow passage 97 opens into the axial flow passage 95. The radially outer end of the second radial flow passage 97 is open radially outward on the outer circumferential surface of the rotary shaft 31 (in the oil groove extending in the circumferential direction in the drawing).

If the compression unit 33 is driven, the housing internal pressure rises. If the internal pressure of the casing rises, the lubricating oil J is pressed up into the axial flow passage 95 from the lower end portion of the rotary shaft 31. The lubricating oil J is subjected to a centrifugal force by the rotation of the rotating shaft 31. By this centrifugal force, the lubricating oil J is distributed from the axial flow passage 95 and supplied to the

radial flow passages

96 and 97. The lubricating oil J having reached the

radial flow passages

96 and 97 flows out on the outer peripheral surface of the rotary shaft 31. The lubricating oil J flowing out on the outer peripheral surface of the rotating shaft 31 is appropriately supplied to the sliding portion of the compression unit 33. The lubricating oil J flows down and returns to the bottom of the hermetic case 34. The lubricating oil J returned to the bottom of the hermetic case 34 is supplied again to the sliding portion of the compression unit 33.

Next, the operation of the multistage rotary compressor 2 will be described.

At the time of starting the multistage rotary compressor 2, electric power is supplied to the stator 35 of the electric motor 32. When electric power is supplied to the stator 35, the rotary shaft 31 rotates about the axis C together with the rotor 36. When the rotary shaft 31 rotates, the

eccentric portions

31b and 31d of the

compression mechanism portions

37 and 38 and the

rollers

45 and 46 rotate eccentrically in the

cylinder chambers

37c and 38 c.

The

rollers

45 and 46 of the

compression mechanism portions

37 and 38 are in rolling contact with the inner circumferential surfaces of the cylinder holes 37b and 38 b. The

blades

18 and 21 function as follows. The vane 21 of the high-stage compression mechanism 38 is in sliding contact with the roller 46 by the urging force of the urging spring 23. The vane 18 of the low stage compression mechanism 37 remains immersed in the vane groove 18c when the casing internal pressure is low. At the time of starting the multistage rotary compressor 2, only the cylinder chamber 38c of the high-stage compression mechanism 38 compresses the gas refrigerant. The cylinder chamber 38c of the high-stage compression mechanism 38 is also divided into a suction side and a compression side at the time of starting the multistage rotary compressor 2. Thereby, the high-stage compression mechanism 38 compresses the gas refrigerant.

After the start-up of the multistage rotary compressor 2, if the inside of the sealed casing 34 is filled with the high-pressure gas refrigerant discharged from the high-stage compression mechanism 38, the following action is exerted. That is, the vane 18 of the low stage compression mechanism 37 is biased toward the roller 45 by the casing internal pressure and starts to slide on the roller 45. If the vane 18 is in sliding contact with the roller 45, the cylinder chamber 37c of the low-stage compression mechanism portion 37 is divided into a suction side and a compression side. Thereby, the compression of the gas refrigerant is started in the low-stage compression mechanism portion 37.

The low-pressure gas refrigerant that has been gas-liquid separated in the accumulator 12 flows through the suction pipe 6. The gas refrigerant is guided into the cylinder chamber 37c of the low-stage compression mechanism 37 through the suction pipe 6. The low-pressure gas refrigerant guided into the cylinder chamber 37c is compressed by the low-stage compression mechanism 37 to have a predetermined intermediate pressure. If the gas refrigerant reaches a predetermined intermediate pressure, the discharge valve device 47 of the partition plate 39 opens. The intermediate-pressure gas refrigerant is discharged into the intermediate-pressure space 39c of the partition plate 39 through the discharge valve device 47.

The gas refrigerant discharged to the intermediate-pressure space 39c is sucked into the high-stage compression mechanism 38 through the intermediate-pressure passage 7.

The gas refrigerant sucked into the high-stage compression mechanism 38 is boosted from the intermediate pressure to a predetermined high pressure. If the gas refrigerant has a predetermined high pressure, the high-stage discharge valve device 49 of the second bearing 42 is opened. The high-pressure gas refrigerant is discharged into the second muffler chamber 44a through the high-stage side discharge valve device 49. The gas refrigerant discharged into the second muffler chamber 44a reaches the first muffler chamber 43a from the discharge passage 33 a. The gas refrigerant is appropriately discharged into the hermetic case 34.

The high-pressure gas refrigerant discharged into the sealed casing 34 circulates through the radiator 3, the expansion device 4, the evaporator 5, and the like, and returns to the low-pressure gas refrigerant. The gas refrigerant returned to the low pressure is introduced again into the cylinder chamber 37c of the low-stage compression mechanism portion 37, and the above-described process is repeated.

The cylinder chamber 37c of the low-stage compression mechanism 37 is divided into a suction side and a compression side by the vane 18. The cylinder chamber 38c of the high-stage compression mechanism 38 is divided into a suction side and a compression side by the vane 21. The

blades

18 and 21 are biased toward the

rollers

45 and 46 by the casing internal pressure. The pressure difference between both sides of the low-stage blade 18 in the advancing/retreating direction is larger than the pressure difference between both sides of the high-stage blade 21 in the advancing/retreating direction. The pressing force of the low-stage blade 18 is larger than that of the high-stage blade 21.

The height of the cylinder body on the low section side is larger than that of the cylinder body on the high section side. The sectional area of the low-stage blade 18 is larger than that of the high-stage blade 21. The pressing force of the low-stage blade 18 is larger than that of the high-stage blade 21.

When the

eccentric portions

31b and 31d rotate, the rotating shaft 31 is deflected. If the rotary shaft 31 is deflected, one ends of the

blades

18, 21 of the opposing

rollers

45, 46 are likely to be brought into contact. If contact of one ends of the

vanes

18, 21 is generated, uneven wear generation occurs in the sliding portions of the

vanes

18, 21 and the

rollers

45, 46. Uneven wear of the sliding portion is likely to occur in the low stage side where both the cross-sectional area of the vane 18 and the pressure difference are large.

In the multistage rotary compressor 2 according to the present embodiment, the lower-stage blade 18 is divided into a plurality of blade members 19. The high-stage-side blade 21 is constituted by a single blade member 22. The cross-sectional area of each blade member 19, 22 is set as follows. That is, the sectional area of the blade member 19 of the low stage compression mechanism portion 37 is smaller than the sectional area of the blade member 22 of the high stage compression mechanism portion 38.

In this configuration, the cross-sectional area of the blade members 19 is reduced on average in the low-stage compression mechanism portion 37. In the low stage compression mechanism 37, the pressure difference between both sides of the vane 18 in the forward and backward direction increases. In the low-stage compression mechanism 37, the roller pressing force of the blade members 19 is reduced. Thereby, the influence of the sliding portion of the roller 45 and the blade 18, which is brought into contact with each other at one end, due to the deflection of the rotary shaft 31 and the like, is suppressed. That is, the roller pressing force of the blade member 19 is alleviated, and uneven wear of the sliding portion between the roller 45 and the blade 18 is suppressed. Therefore, the multistage rotary compressor 2 with high reliability can be provided.

In the multistage rotary compressor 2 according to the present embodiment, the number of vane members 19 of the low-stage compression mechanism portion 37 is larger than the number of vane members 22 of the high-stage compression mechanism portion 38.

In this configuration, the cross-sectional area of the blade members 19 of the low-stage compression mechanism section 37 can be easily reduced. Thus, uneven wear in the sliding portion of the roller 45 and the blade 18 can be suppressed.

In the multistage rotary compressor 2 according to the present embodiment, the plurality of vane members 19 of the low-stage compression mechanism 37 are arranged in the axial direction of the rotary shaft 31.

In this configuration, the cross-sectional area of the blade members 19 of the low-stage compression mechanism section 37 can be easily reduced. Since the cross-sectional area of the blade member 19 is small, the entire blade 18 easily follows the deflection of the rotary shaft 31. Thus, uneven wear on the sliding portion of the roller 45 and the blade 18 can be suppressed.

In the multistage rotary compressor 2 of the present embodiment, the vane 21 of the high-stage compression mechanism portion 38 is formed of a single vane member 22. The high-stage compression mechanism 38 includes an urging spring 23 that urges the single vane member 22 toward the roller 46.

In this configuration, the single vane member 22 and the biasing spring 23 are provided in the high-stage compression mechanism portion 38. The single vane member 22 is used in the high-stage compression mechanism portion 38 having a smaller cross-sectional area and a smaller pressure difference than the low-stage compression mechanism portion 37. Therefore, the influence on the manufacturability and cost of the high-stage compression mechanism portion 38 can be suppressed.

For example, when the biasing member is provided on the lower-stage blade 18 formed of the plurality of blade members 19, the following configuration is preferable. That is, it is preferable to provide a plurality of urging members for each blade member 19. However, this structure may deteriorate the manufacturability and increase the cost. The sectional area and the pressure difference of the vane 18 of the low stage compression mechanism 37 are larger than those of the high stage compression mechanism 38. The blade 18 of the low-stage compression mechanism 37 can sufficiently obtain a pressing force to the roller 45 without providing an urging member. Therefore, the biasing member can be omitted in the low stage compression mechanism portion 37. Therefore, as compared with the case where the biasing member is provided to each of the plurality of blade members 19, the influence on the manufacturability and the cost can be suppressed.

At the time of starting the multistage rotary compressor 2 or the like, the casing internal pressure is not applied (low). In this state, the high-stage compression mechanism 38 compresses the working fluid to increase the casing internal pressure. The low-stage compression mechanism 37 reduces the roller pressing force by an amount corresponding to the biasing force of the biasing member by removing the biasing member of the vane 18.

In the multi-stage rotary compressor 2 of the present embodiment, a biasing member that biases the vane member is provided on one of the low-stage side and the high-stage side (the high-stage compression mechanism portion 38). In the high-stage compression mechanism 38, the vane 21 functions even when the pressure inside the casing is low. That is, even in a state where the internal pressure of the casing is not applied such as when the multistage rotary compressor 2 is started, the high-stage-side blade member 22 is biased toward the roller 46. Therefore, even in a state where the casing internal pressure is not applied, the high-stage compression mechanism 38 can compress and boost the working fluid. That is, even if the pressure inside the casing is low, the pressure inside the casing can be raised by driving the high-stage compression mechanism 38.

If the pressure inside the casing rises, the vane 18 of the low stage compression mechanism 37 also functions, and the low stage compression mechanism 37 starts compression of the working fluid. Therefore, the working fluid can be compressed in stages by the two

compression mechanism portions

37 and 38.

In the multi-stage rotary compressor 2 of the present embodiment, the low-stage compression mechanism 37 and the high-stage compression mechanism 38 are provided with the first bearing 41 and the second bearing 42, respectively. The first bearing 41 and the second bearing 42 support the rotary shaft 31, respectively. The first bearing 41 and the second bearing 42 are provided on the opposite side of the rotating shaft 31 from the partition plate 39 in the axial direction. The axial length L1 of the first bearing 41 on the low stage compression mechanism unit 37 side is longer than the axial length L2 of the second bearing 42 on the high stage compression mechanism unit 38 side. The axial center position cp1 of the sliding portion in the low stage compression mechanism portion 37 is closer to the first bearing 41 than the axial center position cp2 of the cylinder block 37a in the low stage compression mechanism portion 37.

In this configuration, the eccentric portion 31b of the low-stage compression mechanism portion 37 is close to the first bearing 41 whose shaft support portion is long. If the eccentric portion 31b is close to the first bearing 41, the amount of inclination of the eccentric portion 31b (and thus the roller 45) of the low-stage compression mechanism portion 37 caused by the deflection of the rotary shaft 31 is suppressed. If the inclination of the roller 45 is suppressed, the roller 45 of the low-stage compression mechanism portion 37 is suppressed from contacting one end of the sliding portion of the vane 18. Thus, uneven wear of the sliding portion can be suppressed.

In the multistage rotary compressor 2 according to the present embodiment, the intermediate-pressure gas refrigerant in the intermediate pressure chamber 39c is guided to the high-stage compression mechanism portion 38 through the intermediate pressure passage 7. The embodiment is not limited to this configuration. For example, the intermediate-pressure gas refrigerant may be directly sucked from the intermediate pressure chamber 39c into the high-stage compression mechanism 38. For example, the suction port may be formed in the end surface of the partition plate 39 on the high-stage compression mechanism section 38 side. The suction port sucks the gas refrigerant in the intermediate pressure chamber 39c into the cylinder chamber 38c of the high-stage compression mechanism 38.

The refrigeration cycle apparatus 1 of the present embodiment includes: the above-described multistage rotary compressor 2; a radiator 3 connected to a discharge part 15 of the multistage rotary compressor; an expansion device 4 connected to the downstream side of the radiator 3; and an evaporator 5 connected between the downstream side of the expansion device 4 and the introduction portion of the multistage rotary compressor 2.

In this configuration, the refrigeration cycle apparatus 1 includes the multi-stage rotary compressor 2 described above, and the following effects are achieved. That is, the refrigeration cycle apparatus 1 capable of improving the operational reliability and the compression performance over a long period of time can be provided.

According to at least one embodiment described above, the multistage rotary compressor 2 includes: a low-stage compression mechanism 37 that compresses the working fluid to an intermediate pressure; and a high-stage compression mechanism portion 38 that compresses the working fluid at the intermediate pressure to a high pressure. Each of the low-stage compression mechanism section 37 and the high-stage compression mechanism section 38 has

blades

18 and 21 that divide the cylinder chamber into a suction side and a compression side. The blade 18 of the low-stage compression mechanism portion 37 has a plurality of blade members 19. The vane 21 of the high-stage compression mechanism portion 38 has one vane member 22. The cross-sectional area of the blade members 19, on average, is smaller than the cross-sectional area of each blade member 22. Thereby, the blade members 19 of the low-stage compression mechanism 37 are loosened in the average roller pressing force. Further, uneven wear in the sliding portions of the roller 45 and the blade 18 is suppressed. Therefore, the multistage rotary compressor 2 and the refrigeration cycle device 1 having high reliability can be provided.

Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in other various manners, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Description of reference numerals

1 … refrigeration cycle device, 2 … multistage rotary compressor, 3 … radiator, 4 … expansion device, 5 … evaporator, 18 … low stage side blade, 18a … roller contact surface (front end surface), 18b … back surface, 19 … low stage side blade member, 21 … high stage side blade, 21a … roller contact surface (front end surface), 21b … back surface, 22 … high stage side blade member, 23 … biasing spring (biasing member), 31 … rotary shaft, 31b … low stage side biasing portion, 31d … high stage side biasing portion, 32 … electric motor (driving unit), 33 … compression unit, 34 … closed housing (housing), 37 … low stage compression mechanism portion, 37a … low stage side cylinder block, 37c … low stage side cylinder block chamber, cp … axial center position, 38 high stage compression mechanism portion, cylinder block 38a … high stage side cylinder block 72, 3638 c … high stage cylinder block 72, first 3639 bearing chamber 3641, L1 … axial length, 42 … second bearing, L2 … axial length, 45 … low-range side roller, cp1 … axial center position, 46 … high-range side roller

Claims

1. A multistage rotary compressor is provided with:

a housing;

a rotating shaft housed inside the housing;

a drive unit housed in the housing and provided on one axial end side of the rotary shaft; and

a compression unit that is housed in the casing and is provided on the other axial end side of the rotating shaft, the compression unit including a low-stage compression mechanism section that compresses a low-pressure working fluid to an intermediate pressure, a high-stage compression mechanism section that compresses an intermediate-pressure working fluid compressed by the low-stage compression mechanism section to a high pressure, and a partition plate that partitions between the low-stage compression mechanism section and the high-stage compression mechanism section,

the low-stage compression mechanism unit includes:

a low-stage side cylinder body forming a low-stage side cylinder body chamber;

a low-stage-side roller mounted on a low-stage-side eccentric portion provided in the rotary shaft and capable of eccentrically rotating in the low-stage-side cylinder chamber; and

a low-stage side blade having a tip surface abutting against an outer peripheral surface of the low-stage side roller, having a pressure in the housing acting on a back surface thereof, and being capable of advancing and retreating in the low-stage side cylinder chamber, and comprising at least one low-stage side blade member,

the high-stage compression mechanism unit includes:

a high-stage side cylinder body forming a high-stage side cylinder body chamber;

a high-stage side roller mounted on a high-stage side eccentric portion of the rotary shaft and capable of eccentrically rotating in the high-stage side cylinder chamber; and

a high-stage side blade having a tip end surface abutting against an outer peripheral surface of the high-stage side roller, having a pressure in the housing acting on a back surface thereof, and being capable of advancing and retreating in the high-stage side cylinder chamber, and comprising at least one high-stage side blade member,

the working fluid compressed in the high-stage compression mechanism portion is discharged to the inner space of the housing,

in a cross section obtained by cutting the low-stage side blade members and the high-stage side blade members on a plane orthogonal to the advancing and retreating direction of each of the low-stage side blade members, an average cross-sectional area of the low-stage side blade members is smaller than an average cross-sectional area of the high-stage side blade members.

2. The multi-stage rotary compressor of claim 1,

the number of the low-stage-side blade members is larger than the number of the high-stage-side blade members.

3. The multi-stage rotary compressor of claim 1 or 2,

the number of the low-stage-side blade members is plural,

the plurality of low-stage-side blade members are arranged in the axial direction of the rotary shaft.

4. The multistage rotary compressor according to any one of claims 1 to 3,

the number of the low-stage-side blade members is plural,

the number of the high-stage side blade members is one,

the high-stage compression mechanism unit includes a biasing member that biases the high-stage blade member toward the high-stage roller,

the low stage compression mechanism unit does not include a biasing member for biasing the low stage side blade member toward the low stage side roller.

5. The multistage rotary compressor according to any one of claims 1 to 4,

a first bearing and a second bearing for supporting the rotary shaft are provided on the opposite sides of the partition plate of the low-stage compression mechanism section and the high-stage compression mechanism section,

an axial length of a sliding portion with respect to the rotary shaft in the first bearing on the low-stage compression mechanism portion side is longer than an axial length of a sliding portion with respect to the rotary shaft in the second bearing on the high-stage compression mechanism portion side,

an axial center position of a sliding portion between the low stage side eccentric portion of the low stage compression mechanism portion and the low stage side roller is closer to the first bearing than an axial center position of the low stage side cylinder of the low stage compression mechanism portion.

6. A refrigeration cycle device is provided with:

the multi-stage rotary compressor of any one of claims 1 to 5; a radiator connected to a discharge part of the multistage rotary compressor; an expansion device connected to a downstream side of the radiator; and an evaporator connected between a downstream side of the expansion device and an introduction part of the multistage rotary compressor.