JP2004301453A - Partially closed type multistage compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a temperature of a refrigerant discharged from a compressor 1 in accordance with the heat load in a refrigerating circuit. <P>SOLUTION: A compressing means 4 is composed of a front compressing part 11a and a rear compressing part 11b for compressing carbon dioxide. The refrigerant is supplied from the front compressing part 11a to the rear compressing part 11b, here, an inter-cooler 70 is mounted to supply the refrigerant in a cooled state. Further a bypass pipe 77 is connected to the inter-cooler 70 to directly supply the refrigerant from the front compressing part 11 to the read compressing part 11b, when a large amount of heat is required in the refrigerating circuit. A refrigerant supply passage switching unit 78 is mounted to switch the refrigerant supply passages in accordance with the request from the refrigerating circuit. Whereby the temperature of the refrigerant discharged from the compressor 1 can be controlled in accordance with the heat load in the refrigerating circuit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semi-hermetic type multi-stage compressor in which a plurality of casing members are assembled in a hermetically sealed state, a motor, a power conversion means, and a compression means are housed therein, and multi-stage compression is performed using carbon dioxide as a refrigerant.
[0002]
[Prior art]
In the refrigerating circuit, a compressor that compresses a refrigerant is used, and various configurations such as a rotary compressor, a scroll compressor, and a reciprocating compressor have been proposed.
[0003]
Each compressor is a motor such as a motor that generates rotational power, a power conversion unit that converts the rotational power into eccentric rotational power or reciprocating power, a compression unit that moves by the power from the power converter and compresses the refrigerant, A casing housing the motor, the power conversion means and the compression means;
[0004]
Mainly, the casing of a rotary compressor, a scroll compressor, and a reciprocating compressor is composed of a plurality of casing members, in which a motor, a power conversion means and a compression means are housed, and are sealed by welding or the like. It has become.
[0005]
In some reciprocating compressors, a plurality of casing members are assembled by bolting, and a motor, a power conversion means, a compression means, and the like are housed therein.
[0006]
In the present invention, a compressor having a casing assembled by fastening a plurality of casing members by bolts is described as a semi-hermetic compressor.
[0007]
As described above, the semi-hermetic compressor has an advantage that cost reduction can be achieved because means such as welding is not required for the casing, and the reciprocating compressor has a larger compression capacity than the rotary compressor or the scroll compressor. There is an advantage that the product can be manufactured relatively easily.
[0008]
By the way, when the refrigerant is compressed, the refrigerant has a high temperature and a high pressure, and the heat degrades the insulation characteristics of the motor, increases the motor load, and lowers the compression efficiency.
[0009]
From such a viewpoint, in order to improve the compression efficiency, a multi-stage compression system in which the compression means is composed of a plurality of compression sections and the refrigerant is sequentially compressed in each compression section is adopted (see Patent Documents 1 to 3).
[0010]
FIG. 22 is a diagram showing a schematic configuration of such a semi-hermetic type multi-stage compressor. The semi-hermetic type multi-stage compressor 100 is provided on a motor 101 that generates rotational power, a motor shaft 102, and is mounted on the motor shaft 102. A power conversion means 105 for converting rotational power into reciprocating power, comprising a crank 103 (103a, 103b) eccentrically rotating and a connecting rod 104 (104a, 104b) connected to the crank 103, is connected to the connecting rod 104. Piston 106 (106a, 106b), a cylinder 107 (107a, 107b) in which the piston 106 reciprocates, a space (compression chamber) 108 (108a, 108b) surrounded by the cylinder 107 and the piston 106, and the like. Compression having a plurality of compression units 111 (111a, 111b) for compressing refrigerant And a stage 109, it is housed in the casing 110.
[0011]
Note that a room in the casing 110 in which the crank 103 is provided is referred to as a crank chamber 115.
[0012]
FIG. 22 illustrates a case in which two compression units 111a and 111b are provided. One compression unit 111a compresses the refrigerant first, and the compressed refrigerant is further compressed by the other compression unit 11b. It is configured to be compressed.
[0013]
Hereinafter, the compression unit 111a that first compresses the refrigerant will be referred to as a first-stage compression unit, and the compression unit 111b that compresses the refrigerant compressed by the first-stage compression unit 111a will be referred to as a second-stage compression unit. The first and second compression chambers 106 and 108 are also referred to as a first-stage piston 106a, a second-stage piston 106b, a first-stage compression chamber 108a, a second-stage compression chamber 108b, and the like. Described as the compression section, the piston 106, the compression chamber 108, and the like.
[0014]
When the motor 101 rotates, the crank 103 rotates eccentrically with respect to the motor shaft 102, whereby the connecting rod 104 reciprocates, and the piston 106 connected to the connecting rod 104 reciprocates.
[0015]
When the piston 106 descends, the space volume of the compression chamber 108 expands, and the refrigerant is sucked into the compression chamber 108. When the piston 106 rises, the space volume of the compression chamber 108 decreases, and the refrigerant is compressed.
[0016]
In this way, the refrigerant from outside the machine is compressed by the first-stage compression section 111a, sent to the second-stage compression section 111b, further compressed by the second-stage compression section 111b, and discharged outside the machine. In FIG. 22, an arrow pointing to the front-stage compression section 111a indicates a refrigerant sucked from outside the machine, and an arrow from the rear-stage compression section 111b indicates a refrigerant discharged to the outside of the machine.
[0017]
[Patent Document 1]
Japanese Patent Application Laid-Open No. Hei 7-167057 [Patent Document 2]
JP-A-7-127573 [Patent Document 3]
JP-A-7-332773
[Problems to be solved by the invention]
However, in recent years, a compressor using carbon dioxide as a refrigerant has been researched and developed from the viewpoint of environmental problems and the like. In this case, the carbon dioxide is significantly higher in refrigerant pressure and refrigerant temperature than the conventionally used HFC refrigerant and HCFC refrigerant. However, there were the following problems.
[0019]
That is, when carbon dioxide is compressed, the temperature rise increases and the compression efficiency decreases, so the refrigerant compressed in the first-stage compression section 111a is cooled and sent to the second-stage compression section 111b, and further compressed by the second-stage compression section 111b. It discharges outside.
[0020]
Therefore, when cooling or the like is performed using a refrigeration circuit using such a compressor, cooling with high energy efficiency can be performed because of high compression efficiency.
[0021]
However, in a case where hot water is supplied using a refrigeration circuit using such a compressor, when the refrigerant sent from the first-stage compression section 111a to the second-stage compression section 111b is cooled, the refrigerant is discharged from the second-stage compression section 111b accordingly. However, there is a problem that the temperature of hot water is lowered because the temperature of the refrigerant is lowered.
[0022]
Accordingly, it is an object of the present invention to provide a semi-hermetic multi-stage compressor in which an optimal compression method can be selected according to the temperature of a refrigerant required in a refrigeration circuit.
[0023]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is a motor that generates rotational power, a power conversion unit that converts the rotational power to reciprocating power, and reciprocates by reciprocating power from the power conversion unit, Compression means having a plurality of compression parts for compressing the refrigerant, and a casing in which a plurality of casing members are assembled in a closed state and housing a motor, a power conversion means and a compression means, are provided. In a semi-hermetic type multi-stage compressor in which the compressed refrigerant is further compressed and discharged by the downstream compression section, the refrigerant is carbon dioxide, and the bypass connects the upstream compression section and the downstream compression section. A pipe, connected in parallel with the bypass pipe, an intercooler that radiates the flowing refrigerant, and the refrigerant compressed by the compression section on the front stage side is supplied to the compression section on the downstream side via the bypass pipe, A refrigerant supply path switching device that switches whether to supply the refrigerant to the compression section on the subsequent stage via the intercooler, so that an optimal compression method can be selected according to the temperature of the refrigerant required in the refrigeration circuit. Features.
[0024]
The invention according to claim 2 is characterized in that the intercooler is formed by press-fitting a plurality of fins into a pipe at predetermined intervals.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a semi-hermetic type multi-stage compressor 1 according to the present embodiment, and FIG. 2 is a sectional view taken along the line AA of FIG. Hereinafter, the semi-hermetic type multi-stage compressor 1 is abbreviated as the compressor 1 as appropriate.
[0026]
The compressor 1 includes a motor 2 that generates rotational power, a power conversion unit 3 that converts the rotational power generated by the motor 2 into reciprocating power, and a refrigerant that is driven by the reciprocating power converted by the power converting unit 3 to convert the refrigerant. The compression means 4 for compressing, the casing 5 for accommodating them, and the like are mainly used to compress the carbon dioxide refrigerant.
[0027]
In the present embodiment, a two-stage compressor in which the compression means 4 includes a front-stage compression unit 11a and a rear-stage compression unit 11b will be described as an example of the multistage compressor 1, but the present invention is not limited to this. It is added in advance that the present invention can be applied to the compressor 1 that compresses the refrigerant of carbon dioxide in two or more compression units.
[0028]
The casing 5 has a casing main body 5a made of spheroidal graphite cast iron or the like, a motor side lid 5b, a partition plate 5c, a bottom lid 5d, a crank side lid 5e, a shaft lid 5f, a head plate 5g, a cylinder head 5h, and the like. The motor-side lid 5b and the like are bolted to the casing main body 5a with a plurality of bolts 14 via a sealing material 13, and are assembled in a sealed state.
[0029]
Lubricating oil 15 for lubricating each sliding portion of the compressor 1 is stored at the bottom of the casing main body 5a, and the amount of oil can be confirmed by a sight glass (a see-through window) 16. .
[0030]
The partition plate 5c is provided with a plurality of through holes 17 (17a, 17b). The partition plate 5c divides the internal space of the casing body 5a into a motor chamber 18 and a crank chamber 19, and through the through holes 17, The atmosphere between the motor chamber 18 and the crank chamber 19 can come and go, and the lubricating oil 15 can come and go.
[0031]
In addition, a large number of casing fins 20 are formed on the outer surface of the casing body 5a (particularly, the outer surface corresponding to the motor chamber 18), so that the heat of the casing 5 can be efficiently radiated.
[0032]
A lubricating oil pocket 21 is formed on the motor side lid 5b, a main journal 22 is formed on the partition plate 5c, and a sub journal 23 is formed on the crank side lid 5e.
[0033]
The power conversion means 3 is provided integrally with the motor shaft 24 of the motor 2 and cranks 25 (25a, 25b) for converting rotational power into reciprocating power by rotating eccentrically with respect to the axis of the motor shaft 24. And a connecting rod 26 (26a, 26b) connected to the crank 25.
[0034]
The crank 25 and the connecting rod 26 include a front-stage crank 25a, a rear-stage crank 25b, a front-stage connecting rod 26a, and a rear-stage connecting rod 26b corresponding to the front-stage compression unit 11a and the rear-stage compression unit 11b.
[0035]
The motor 2 is a canned motor fitted and mounted in the motor chamber 18 and has a main lubricating oil passage 28 formed by drilling a hole of a predetermined diameter in the axis of the motor shaft 24. A sub-lubricating oil passage 29 is formed, which forms a lubricating passage for the lubricating oil 15 to the large end and the small end of the lubricating oil 15 and a lubricating passage for the lubricating oil 15 to the main journal 22 and the sub-journal 23.
[0036]
One end of the motor shaft 24 is inserted into the lubricating oil pocket 21 from the side surface of the lubricating oil pocket 21, and the other end is inserted through the main journal 22 and engages with the auxiliary journal 23 provided on the crank side lid 5 e. Together, the main journal 22 and the sub-journal 23 rotatably support the journal.
[0037]
Further, a lubricating oil scraper blade 30 is attached to a rotor of the motor 2 so as to rotate together with the motor shaft 24.
[0038]
As a result, when the lubricating oil scooping wing 30 rotates with the rotation of the motor 2, the lubricating oil 15 stored at the bottom of the casing 5 adheres to the lubricating oil scooping wing 30 and is scooped up. The lubricating oil 15 accumulates in the lubricating oil pocket 21.
[0039]
Since the motor shaft 24 is inserted through the lubricating oil pocket 21 and the main lubricating oil passage 28 is formed in the motor shaft 24, the lubricating oil 15 accumulated in the lubricating oil pocket 21 is And flows toward the crank side lid 5e.
[0040]
The lubricating oil 15 that has flowed into the main lubricating oil passage 28 receives centrifugal force due to the rotation of the motor shaft 24 and shunts to the sub-lubricating oil passage 29. It is supplied to a sliding surface such as an end.
[0041]
As will be described later, the lubricating oil 15 is also supplied between the piston and the cylinder in the compression means 4 to increase the confidentiality of the compression chamber.
[0042]
The lubricating oil 15 not used for lubrication of each sliding portion (excess lubricating oil) is discharged from the lubricating oil return path 31 formed in the crank side lid 5e and returns to the bottom of the casing 5.
[0043]
A connection terminal box 33 in which a connection terminal 32 for supplying power to the motor 2 is accommodated is provided in the casing main body 5 a at a position above the motor 2.
[0044]
FIG. 3 is a diagram exemplifying the seal member 13 mounted between the head plate 5g and the cylinder head 5h as the seal member 13. 3 is a top view of the sealing material 13, FIG. 4 is a cross-sectional view taken along the line BB shown in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line CC shown in FIG.
[0045]
The sealing material 13 is composed of a metal gasket 35 and an elastic sheet gasket 36. The metal gasket 35 is formed of a material having a high tensile strength such as a stainless steel plate (preferably SUS316) and has a portion corresponding to the sealing surface. Are formed with beads 37 (37a, 37b).
[0046]
The bead 37 is basically a full bead 37a as shown in FIG. 4, but in a place where it is difficult to secure a space for the full bead 37a due to the presence of the bolt holes 27, a half bead 37b is formed as shown in FIG. I have. The dotted line in FIG. 3 indicates a peak or a valley of the bead 37.
[0047]
In the compressor 1 according to the present invention, carbon dioxide is used as a refrigerant. At this time, the discharge pressure of the latter-stage compression section 11b becomes extremely high at about 12 MPa. For example, conventionally used cold-rolled steel is used as a material. In the metal gasket 35, it is difficult to keep the inside of the casing 5 airtight for a long period of time because the metal gasket 35 is expanded and expanded by this pressure.
[0048]
Therefore, a metal gasket 35 made of stainless steel or the like having a high tensile strength is used to prevent the metal gasket 35 from extending due to the pressure of the refrigerant.
[0049]
Such a sealing material 13 is used when the motor-side cover 5b, the crank-side cover 5e, the bottom cover 5d, and the like are attached to the casing body 5a. If the discharge pressure is lower than the discharge pressure of 11b (for example, the atmospheric pressure or the discharge pressure of the pre-compression unit 11a), cold-rolled steel may be used as the material of the metal gasket 35.
[0050]
That is, a metal gasket 35 made of stainless steel may be used for sealing high pressure parts such as the cylinder head 5h, and a metal gasket 35 made of cold rolled steel may be used for parts having a lower pressure. .
[0051]
The elastic sheet gasket 36 is formed of an elastic member having resistance to high temperature and high pressure such as nitrile rubber and having oil resistance, and is disposed vertically so as to sandwich the metal gasket 35.
[0052]
If the bead 37 is not formed on the metal gasket 35, the surface pressure of the metal gasket 35 becomes low, and it becomes difficult to maintain airtightness.
[0053]
However, when the beads 37 are formed, the peaks and valleys of the beads 37 are used as starting points and have elasticity, so that the surface pressure is increased and the airtightness can be improved and maintained.
[0054]
The compression means 4 has the front-stage compression section 11a and the rear-stage compression section 11b as described above, and each compression section 11 is a cylinder 40 (40a, 40b) also serving as the casing body 5a, and a piston reciprocating in the cylinder 40. 41 (41a, 41b), a space (compression chamber) 42 (42a, 42b) formed by the cylinder 40 and the piston 41, and the like.
[0055]
Note that the phase of the reciprocating motion of the front-stage piston 41a and the rear-stage piston 41b is shifted by 180 degrees, and when the front-stage piston 41a descends (refrigerant suction), the rear-stage piston 41b rises to compress the refrigerant. Once set, the load applied to the motor 2 is made uniform.
[0056]
The diameters of the front-stage piston 41a and the rear-stage piston 41b are set to be larger in the front-stage piston 41a, and the distance (stroke of the piston 41) when the front-stage piston 41a and the rear-stage piston 41b reciprocate. Are set to the same length.
[0057]
As a result, the excluded volume in the first-stage compression section 11a is larger than the excluded volume in the second-stage compression section 11b, so that multistage compression is possible.
[0058]
Needless to say, when performing the multi-stage compression, the necessary volume of the first-stage compression section 11a is larger than the second-stage compression section 11b. The requirement may be satisfied by making the reciprocating movement distance of the front compression unit 11a longer than the reciprocating movement distance of the rear compression unit 11b.
[0059]
The piston 41 is pin-coupled to the small end of the connecting rod 26 by a pin 45 so as to swing freely, and has a ring groove formed on the surface thereof. Is inserted.
[0060]
The seal of the compression chamber 42 with respect to the crank chamber 19 is ensured by the piston ring 46 abutting on the cylinder 40 and sliding. However, the seal characteristic is improved without increasing the sliding resistance against the reciprocating motion of the piston 41. In order to increase the distance, the distance between the surface of the piston 41 and the surface of the cylinder 40 is set to a very small dimension (clearance), so that the piston ring 46 and the surface of the piston 41 perform a labyrinth sealing effect.
[0061]
Further, as described above, the lubricating oil 15 supplied to the connecting portion between the connecting rod 26 and the piston 41 via the auxiliary lubricating oil passage 29 of the connecting rod 26 is transmitted through the pin 45 to the piston ring 46. To improve the airtightness between the piston 41 and the cylinder 40.
[0062]
By the way, in the latter-stage compression section 11b, since the refrigerant compressed in the former-stage compression section 11a is compressed, the differential pressure between the latter-stage compression chamber 42 and the crank chamber 19 becomes larger than the differential pressure between the former-stage compression chamber 42a and the crank chamber 19. Accordingly, the amount of refrigerant leaking from the rear compression chamber 42b to the crank chamber 19 becomes larger than the amount of refrigerant leaking from the front compression chamber 42a to the crank chamber 19.
[0063]
In such a case, the amount of leakage can be suppressed by increasing the contact force of the piston ring 46 mounted on the rear-stage piston 41b against the rear-stage cylinder 40b. There is a problem that a large torque is required to drive the motor. Further, there is a problem that the amount of wear increases due to a large contact force.
[0064]
Therefore, in the present invention, as shown in FIG. 6, the number of piston rings 46 attached to the rear piston 41b having a large differential pressure is made larger than the number of piston rings 46 attached to the front piston 41a. The amount of refrigerant leaking from the compression chamber 42 to the crank chamber 19 is reduced while suppressing an increase in the load on the motor 2.
[0065]
The piston 41 is swingably connected by a pin 45 at a small end of the connecting rod 26, and reciprocates by reciprocating power from the connecting rod 26.
[0066]
At this time, the line of action of the reciprocating power is on a line connecting the center position p1 at the small end of the connecting rod 26 and the center position p2 at the large end, as shown in FIG. (In FIG. 7, this shift amount is indicated by θ).
[0067]
7A shows a case where the connecting rod 26 is biased rightward with respect to the surface of the cylinder 40, and FIG. 7B shows a case where the connecting rod 26 is biased leftward with respect to the surface of the cylinder 40. Shows the case. FIG. 7C shows the inclination of the piston 41 when the connecting rod 26 is deviated rightward with respect to the surface of the cylinder 40 (dotted line), and shows the inclination of the piston 41 when deviated leftward (solid line). ).
[0068]
As described above, the piston 41 reciprocates with an inclination of 2θ at the maximum on the outward return path, and the piston 41 may come into direct contact with the cylinder 40 (a circled area in FIG. 7C). The piston 41 may be scratched or worn, and the worn portion may adhere to the cylinder 40.
[0069]
In particular, conventionally, the piston 41 is conventionally formed of aluminum for the purpose of weight reduction, and aluminum is a soft and viscous metal, so that the piston 41 is damaged or worn, and the wear on the cylinder 40 is reduced. There is a problem that adhesion easily occurs.
[0070]
If the piston 41 or the cylinder 40 is damaged or worn as described above, refrigerant leakage from the compression chamber 42 to the crank chamber 19 increases, or a large torque (increase in motor load) is required to reciprocate the piston 41. Or become.
[0071]
Therefore, in the present invention, as shown in FIG. 8, the piston 41 is made of aluminum as a base material to reduce the weight while providing a surface hardened portion 47 on the surface thereof to reduce the deterioration of the sealing characteristics and the like. An increase in motor load is suppressed.
[0072]
The surface hardened portion 47 is an oxide film of alumina formed by anodizing the surface of the piston 41 made of aluminum (for example, alumite treatment or molybdenum treatment by secondary electrolysis).
[0073]
The alumite treatment or molybdenum treatment by secondary electrolysis is a surface treatment method in which a porous and transparent oxide film (alumina film) is formed by electrolysis on an aluminum substrate. The hard alumite treatment has a higher current than ordinary anodic oxidation. This is a method of treating the surface by flowing aluminum, which has the characteristics of increasing the hardness of the aluminum film and increasing the corrosion resistance and wear resistance.
[0074]
Of course, as a method of increasing the surface hardness of the piston 41, for example, a method of forming the piston 41 with an alloy of aluminum and silicon is also possible. Since the hardness of this alloy of aluminum and silicon is higher than that of aluminum alone, there is an advantage that the surface hardened portion 47 can be formed at the same time as the strength of the piston 41 is increased.
[0075]
As described above, when the carbon dioxide is compressed, the pressure becomes high and the temperature becomes high. However, a large load is applied to the piston 41 due to the pressure, and the load is transmitted to the crank 25 via the connecting rod 26.
[0076]
However, conventionally, since the connecting rod 26 is formed of aluminum and a bearing is used for a connecting portion thereof, there is a problem that the cost is increased, the weight of the bearing is increased, and the device becomes heavy.
[0077]
In addition, when the bearing is worn by a large load, the heat of the piston 41 whose temperature has been increased by the refrigerant becomes difficult to transfer to the connecting rod 26 and the crank 25 (the heat of the piston 41 deteriorates) and is sucked into the compression chamber 42. The cooled refrigerant is heated by the heat of the piston 41, and the compression efficiency is reduced due to the reduction in the amount of the refrigerant sucked.
[0078]
In view of this, in the present invention, as shown in FIG. 9, a wear-resistant portion 49 for improving the wear resistance of the connection portion is provided without providing the bearing in the connection portion.
[0079]
As the wear-resistant portion 49, an advantage that the connecting rod 26 is made of an aluminum alloy having a large silicon content to increase the strength and hardness while reducing the weight of the connecting rod 26 and that the wear-resistant portion 49 can be formed at the same time. There is.
[0080]
At this time, the composition ratio of the connecting rod 26 is preferably 10 wt% to 12 wt% of the aluminum alloy and silicon.
[0081]
Of course, wear at the connecting portion of the connecting rod 26 is a problem. For example, a method of forming the connecting rod 26 from aluminum and subjecting the connecting portion to surface treatment such as alumite treatment, A method in which only a surface layer is made of an aluminum-silicon alloy by forming a silicon film and performing a heat treatment is also possible.
[0082]
The cylinder head 5h is a dish-shaped member. As shown in FIG. 2, the internal space is partitioned by a partition plate 50 to form a front suction chamber 51, a front discharge chamber 52, a rear suction chamber 53, and a rear discharge chamber 54. ing.
[0083]
The front-stage suction chamber 51 is a room to which a refrigerant from outside the machine is supplied, and the refrigerant in the room is supplied to the front-stage compression chamber 42a. The first-stage discharge chamber 52 is a room where the refrigerant compressed by the first-stage compression section 11a is discharged. The rear suction chamber 53 is a room to which the refrigerant from the front discharge chamber 52 is supplied and supplies the refrigerant to the rear compression unit 11b. The second-stage discharge chamber 54 is a room where the refrigerant compressed by the second-stage compression section 11b is discharged, and the refrigerant is supplied outside the machine.
[0084]
At this time, the head plate 5g corresponding to the front-stage suction chamber 51, the front-stage discharge chamber 52, the rear-stage suction chamber 53, and the rear-stage discharge chamber 54 has a front-stage suction hole 55, a front-stage discharge hole 56, a rear-stage suction hole 57, and a rear-stage discharge hole, respectively. The front suction chamber 51 has a front suction port 59, the front discharge chamber 52 has a front discharge port 60, the rear suction chamber 53 has a rear suction port 61, and the rear discharge chamber 54 has a rear discharge port 62. Is formed.
[0085]
The front suction hole 55 has a front suction valve 63, the front discharge hole 56 has a front discharge valve 64, the rear suction hole 57 has a rear suction valve 65, and the rear discharge hole 58 has a rear discharge valve 66. Is provided so as to close the hole.
[0086]
Each of these valves is a leaf spring-shaped valve. The front-stage suction valve 63 and the rear-stage suction valve 65 are mounted on the head plate 5g surface on the compression chamber 42 side, and the front-stage discharge valve 64 and the rear-stage discharge valve 66 are connected to the front-stage discharge chamber 52 and It is attached to the surface of the head plate 5g on the side of the second-stage discharge chamber 54, and functions as a check valve so that the flow of the refrigerant is in one direction.
[0087]
As shown in FIG. 2, the first-stage discharge chamber 52 and the second-stage suction chamber 53 are connected by an intercooler 70 so that the refrigerant supplied from the first-stage discharge chamber 52 to the second-stage suction chamber 53 radiates heat in the intercooler 70. It has become.
[0088]
As shown in FIG. 10, the intercooler 70 is a pipe formed by press-fitting a large number of fins 72 at a predetermined interval into a pipe 71, so that the refrigerant flowing in the pipe can exchange heat with the atmosphere and radiate heat. It has become.
[0089]
Since the refrigerant of carbon dioxide becomes high in temperature even when discharged from the first-stage compression unit 11a, if it is supplied to the second-stage compression unit 11b as it is, the amount of refrigerant sucked into the second-stage compression unit 11b is reduced, and the compression efficiency is improved. I can't.
[0090]
For this reason, the refrigerant from the first-stage compression section 11a is supplied to the second-stage compression section 11b via the intercooler 70, and the heat is radiated by the intercooler 70, thereby lowering the temperature of the refrigerant and improving the compression efficiency. .
[0091]
With such a configuration, the rotation of the motor 2 causes the crank 25 to eccentrically rotate with respect to the motor shaft 24, and the connecting rod 26 connected to the crank 25 reciprocates.
[0092]
A piston 41 is connected to the connecting rod 26, and the front-stage piston 41a and the rear-stage piston 41b have a phase and reciprocate.
[0093]
When the pre-stage piston 41a descends, the space volume of the pre-stage compression chamber 42a expands to generate suction pressure. The pre-stage suction valve 63 is opened by this suction pressure, and refrigerant outside the machine enters the pre-stage suction chamber 51 from the suction port. From there, it flows into the front chamber through the front suction hole 55.
[0094]
Next, when the front-stage piston 41a rises, the space volume of the front-stage chamber is reduced, and the refrigerant in the front-stage chamber is compressed. When the pressure of the refrigerant reaches a predetermined pressure, the first-stage discharge valve 64 is opened, and the refrigerant in the first-stage chamber is discharged to the first-stage discharge chamber 52.
[0095]
Similarly, when the latter-stage piston 41b descends, the space volume of the latter-stage compression chamber 42b expands to generate suction pressure, and the latter-stage suction valve 65 opens to allow the refrigerant in the former-stage discharge chamber 52 to enter the latter-stage suction chamber 53, From there, it flows into the rear compression chamber 42b through the rear suction hole 57.
[0096]
Next, when the rear piston 41b rises, the space volume of the rear compression chamber 42b is reduced, and the refrigerant in the rear compression chamber 42b is compressed. When the pressure of the refrigerant reaches a predetermined pressure, the second-stage discharge valve 66 is opened, and the refrigerant in the second-stage compression chamber 42b is discharged to the second-stage discharge chamber 54, and the refrigerant is discharged from the discharge port to the outside of the machine.
[0097]
As described above, since the connecting rod 26 is provided with a wear-resistant portion, even if carbon dioxide is compressed, wear at the connecting portion of the connecting rod 26 can be suppressed, and the life is extended and the reliability is improved. I do.
[0098]
In addition, since the metal gasket 35 of the sealing material 13 is formed of a material having high tensile strength, the sealing performance is improved, and the reliability is improved.
[0099]
In addition, since the surface hardened portion 47 is provided on the piston 41, the inconvenience of scratching the piston 41 and attaching wear to the cylinder 40 can be suppressed while reducing the weight of the compressor 1, thereby improving reliability. I do.
[0100]
Further, by increasing the number of piston rings 46 attached to the rear piston 41b to be larger than the number of piston rings 46 attached to the front piston 41a, the amount of refrigerant leaking from the rear compression chamber 42b to the crank chamber 19 and the like can be suppressed, and the compression efficiency can be reduced. Is improved.
[0101]
By the way, such a compressor 1 is used in a refrigeration circuit. In the refrigeration circuit, there is a case where heat is used or a case where cold is used. Particularly, when a large amount of high temperature heat is required, There is an advantage that the required amount of heat can be easily satisfied by not radiating heat by the intercooler 70.
[0102]
This will be described with reference to a refrigeration circuit shown in FIG. The refrigeration circuit includes the compressor 1, the first heat exchanger 80, the pressure reducing device 81, and the second heat exchanger 82 according to the present invention as main components, and uses refrigerant when using warm heat and when using cold heat. A four-way valve 83 for switching the circulation direction is provided. In the following description, it is assumed that the first heat exchanger 80 provides hot or cold heat.
[0103]
FIG. 11 is a diagram schematically showing a configuration of the compressor 1 when the compressor 1 shown in FIG. 1 is used for a refrigeration circuit, and solid arrows in FIG. When cold heat is provided, the dotted arrow indicates the direction of circulation of the refrigerant when the first heat exchanger 80 provides warm heat.
[0104]
A heater or a water heater can be exemplified as a device utilizing warm heat, and a cooling device or a showcase can be exemplified as a device utilizing cold heat.
[0105]
In the case of using heat, the heat of the refrigerant that has been compressed to a high temperature is used. In the case of heating by air conditioning, 30 to 40 ° C, and in the case of heating by floor heating equipment, 20 to 35 ° C, In the case of a water heater, a temperature of 50 to 90 ° C. is required. In the case of using cold heat, the latent heat of evaporation of the refrigerant is used, and the temperature of the refrigerant discharged from the compressor 1 is preferably lower.
[0106]
As described above, depending on the type of heat utilization device such as a heater, there are cases where it is preferable that the temperature of the refrigerant discharged from the compressor 1 is higher and that where it is lower.
[0107]
In particular, in a water heater in which a large amount of hot water is continuously used (for example, a water heater used in a large-scale kitchen such as a restaurant or a hot water heater used to fill a bath), the refrigerant temperature is possible. It is desirable to be as high as possible.
[0108]
Therefore, a bypass pipe 77 is provided in parallel with the intercooler 70, and a refrigerant supply path switching device 78 such as an electromagnetic valve is provided to supply the refrigerant from the first-stage compression unit 11a to the second-stage compression unit 11b. Whether to supply via the bypass 70 or via the bypass pipe 77 is controlled by a refrigerant supply path switch 78.
[0109]
Thereby, when a high-temperature refrigerant is required, the refrigerant from the first-stage compression section 11a is supplied to the second-stage compression section 11b via the bypass pipe 77. When a high-temperature refrigerant is not required, the refrigerant from the first-stage compression section 11a is supplied. The refrigerant is supplied to the post-stage compression section 11b via the intercooler 70.
[0110]
In the case where the refrigerant is supplied to the latter compression section 11b via the bypass pipe 77, a temperature rise of, for example, 20 ° C is expected compared to the case where the refrigerant is supplied to the latter compression section 11b via the intercooler 70.
[0111]
When using cold heat, the refrigerant compressed in the first-stage compression section 11a releases heat in the intercooler 70 and is supplied to the second-stage compression section 11b and compressed.
[0112]
The refrigerant compressed in the second-stage compression section 11b is supplied to the second heat exchanger 82 through the four-way valve 83, exchanges heat with the outside air and the like in the second heat exchanger 82, and is decompressed by the decompression device 81. After evaporating in the first heat exchanger 80, the process returns to the compressor 1 via the four-way valve 83.
[0113]
The partner with which the refrigerant exchanges heat in the first heat exchanger 80 is room air when the cold heat utilization device is an air conditioner, and is room air when the device is a showcase, and the latent heat of evaporation at that time. Is supplied by the room air or the like, thereby lowering the temperature of the room air or the like, thereby performing cooling or the like.
[0114]
On the other hand, in the case of heating by an air conditioner, heating by a floor heating device, a water heater that is used only for a short time, and that is used only for a small amount, the refrigerant compressed in the pre-compression unit 11a passes through the intercooler 70. The refrigerant supplied to the second-stage compression section 11b and compressed by the second-stage compression section 11b is supplied to the first heat exchanger 80 via the four-way valve 83.
[0115]
The refrigerant exchanges heat with room air or the like in the first heat exchanger 80 to heat the room air or the like and is supplied to the pressure reducing device 81 to be decompressed. Thereafter, the refrigerant exchanges heat with outside air in the second heat exchanger 82 to evaporate, and returns to the compressor 1 through the four-way valve 83.
[0116]
When a large amount of hot water is used, the refrigerant compressed in the first-stage compression section 11a is directly supplied to the second-stage compression section 11b, and the refrigerant compressed in the second-stage compression section 11b is supplied to the four-way valve 83. To the first heat exchanger 80.
[0117]
The refrigerant exchanges heat with city water or the like in the first heat exchanger 80 to heat the city water or the like, and is supplied to the pressure reducing device 81 to be decompressed. Thereafter, the refrigerant exchanges heat with outside air in the second heat exchanger 82 to evaporate, and returns to the compressor 1 through the four-way valve 83.
[0118]
As described above, since the temperature of the refrigerant from the compressor 1 can be adjusted according to the type of the heat utilization device and the like, it is possible to efficiently supply hot or cold heat.
[0119]
Next, a second embodiment of the present invention will be described with reference to the drawings. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
[0120]
As described above, when carbon dioxide is compressed, a high temperature and a high pressure are applied. Therefore, a large load is applied to the main journal 22, the sub-journal 23, and the connecting rod 26, and abrasion of these sliding portions becomes severe.
[0121]
In addition, the motor 2 overcomes such a large load and drives the piston 41 to generate a large amount of heat. In addition, since the crank chamber 19 and the motor chamber 18 in which the motor 2 is disposed are closed spaces, efficient operation is achieved. Cannot cool.
[0122]
Further, since the pressure is different between the first-stage compression unit 11a and the second-stage compression unit, the driving torques for driving them are also different, and a large torque imbalance occurs. For this reason, a motor 2 that can withstand such a large torque imbalance is required, and the connecting portion such as the connecting rod 26 that drives the rear-stage compression section wears more than the connecting portion such as the connecting rod 26 that drives the front-stage compression section 11a. In addition, an unbalance in life occurs between the first-stage compression unit 11a and the second-stage compression unit.
[0123]
Further, the heat generated when the refrigerant is compressed causes the temperature of the piston 41 and the cylinder 40 to rise, and the heat of the cylinder 40 is radiated directly to the outside air via the casing 5, but the heat of the piston 41 is 26, the crank 25, the motor shaft 24, the main journal 22, the sub-journal 23, etc., conduct heat to the casing 5 and radiate heat from the casing 5 to the outside air. Therefore, when the wear of the connecting portion between the connecting rod 26 and the piston 41 and the like progresses, the heat of the piston 41 does not smoothly transfer to the casing 5.
[0124]
In order to cope with such a problem, in the first embodiment, a wear-resistant portion 49 is provided on a connecting portion of the connecting rod 26 or the like.
[0125]
However, since the wear-resistant portion 49 does not reduce the load applied to the connecting rod 26, it cannot cope with a torque imbalance or the like.
[0126]
Accordingly, in the present embodiment, the pressure in the compression chamber 42 and the pressure in the crank chamber 19 and the motor chamber 18 are reduced by setting the pressure in the crank chamber 19 and the motor chamber 18 to be substantially the same as the discharge pressure in the preceding stage. It is intended to be reduced.
[0127]
For this reason, as shown in FIG. 12, a communication portion 73 having a minute diameter (for example, a diameter of about 0.5 mm) is formed by piercing the casing main body 5a so as to communicate the pre-stage discharge chamber 52 with the crank chamber 19 and the like. are doing.
[0128]
FIG. 12 is a simplified view of the detailed configuration of the compressor 1 shown in FIG. 1 in order to explain the configuration of the communication unit 73.
[0129]
Due to this communication part 73, the pressure in the crank chamber 19 and the like becomes close to the pressure in the pre-discharge chamber 52, and the differential pressure between the pressure in the crank chamber 19 and the pressure in the compression chamber 42 becomes small, and Inconvenience can be prevented.
[0130]
The reason why the diameter of the communication portion 73 is small is that if the diameter of the communication portion 73 is small enough to allow the refrigerant to easily flow between the front discharge chamber 52 and the crank chamber 19, the refrigerant compressed by the front compression portion 11a will This is to prevent the compression efficiency from lowering due to the difficulty in being supplied to the compression section 11b.
[0131]
That is, since the excluded volume of the first-stage compression section 11a is larger than the excluded volume of the second-stage compression section 11b, the fluctuation of the pressure in the crank chamber 19 and the like is controlled by the movement of the first-stage piston 41a, and the first-stage piston 41a rises. Then, the pressure in the crank chamber 19 and the like decreases, and when the pre-stage piston 41a descends, the pressure in the crank chamber 19 and the like increases.
[0132]
Therefore, when the refrigerant can easily move between the upstream discharge chamber 52 and the crank chamber 19 and the like, the refrigerant moves between the upstream discharge chamber and the crank chamber 19 and the like in accordance with the movement of the front piston 41a, It becomes difficult to be supplied to the subsequent compression section.
[0133]
In addition, since the space volume of the crank chamber 19 and the like is sufficiently larger than the space volume of the compression chamber 42, when the refrigerant compressed in the pre-compression section 11a flows into the crank chamber 19 and the like, it expands there and the compression efficiency is reduced. descend.
[0134]
For this reason, in the present invention, the communicating portion 73 has a small diameter. The definition of the minute diameter is clear from the above description, but the expression can be easily changed as follows.
[0135]
That is, the compressor 1 has a diameter that allows the refrigerant to flow so that the pressure in the crank chamber 19 and the like becomes equal to the pressure in the pre-stage discharge chamber 52 when the compressor 1 is stopped, and the pressure in the pre-stage discharge chamber 52 during operation. The diameter is such that the pressure in the crank chamber 19 and the like responds to the fluctuation very slowly.
[0136]
In order to form such a small-diameter communication portion 73 in the casing 5, it is necessary to drill at least a distance longer than the length of the piston 41, and such a small-diameter hole is formed over a long distance. It is very difficult to perform such a task, and a special tool is required or a high level of technology is required, which causes an increase in cost.
[0137]
In such a case, for example, as shown in FIG. 13, by increasing the diameter of the communicating portion 73 to a point in the middle and making the tip of the communicating portion 73 a small diameter, the distance of the small diameter portion is shortened, and the above-described problems such as an increase in cost are caused. Can be handled.
[0138]
Further, the communication portion 73 may be formed not only by forming a hole in the casing 5 but also by connecting the upstream discharge chamber 52 and the crank chamber 19 with a small-diameter thin tube as shown in FIG.
[0139]
In the above description, the case where the crank chamber 19 and the like and the upstream discharge chamber 52 are connected by the communication portion 73 has been described. However, the upstream discharge chamber and the downstream suction chamber are different from each other only in the phase of the pressure fluctuation by approximately 180 degrees. Therefore, the same effect can be obtained even if the crank chamber 19 and the like and the rear suction chamber 53 are connected by the communication portion 73 as shown in FIG. Needless to say.
[0140]
Next, a third embodiment of the present invention will be described with reference to the drawings. Note that the same components as those of the above-described embodiments are denoted by the same reference numerals, and description thereof will be appropriately omitted.
[0141]
In the second embodiment, in order to reduce the differential pressure between the pressure in the compression chamber 42 and the pressure in the crank chamber 19 and the motor chamber 18 and reduce the load applied to the connecting rod 26 and the like, The small-diameter communication portion 73 communicates with the crank chamber 19 and the like.
[0142]
On the other hand, in the present embodiment, the refrigerant from the first-stage discharge chamber 52 is guided to the motor chamber 18 and flows from the motor chamber 18 through the crank chamber 19 to increase the pressure in the crank chamber 19. The refrigerant is supplied to the rear suction chamber.
[0143]
With such a configuration, in addition to the effects described in the second embodiment, a new effect that the motor 2 can be cooled can be taught.
[0144]
For this reason, in the present embodiment, as shown in FIG. 16, the front discharge chamber 52 and the motor chamber 18 are connected by the refrigerant introduction pipe 74, and the crank chamber 19 and the rear suction chamber 53 are connected to the refrigerant return pipe 75 ( The intercooler 70 is connected to the refrigerant introduction pipe 74.
[0145]
FIG. 16 is a simplified view of the detailed configuration of the compressor 1 shown in FIG. 1 for explaining the configuration of the refrigerant introduction pipe 74 and the refrigerant return pipe 75.
[0146]
An end of the refrigerant introduction pipe 74 on the motor chamber 18 side is provided near a coil end (an end of a stator or a rotor) of the motor 2 so that refrigerant from the upstream discharge chamber 52 blows on the coil end. It has become.
[0147]
The end of the refrigerant return pipe 75 on the side of the crank chamber 19 is provided at a position where the lubricating oil 15 discharged from the lubricating oil return path 31 does not easily adhere, and at a position close to the piston 41.
[0148]
As a result, the refrigerant flows in the motor chamber 18 and the crank chamber 19 as indicated by the dotted arrows in FIG. That is, the refrigerant from the upstream discharge chamber 52 blows against the coil end of the motor 2, cools the motor 2 while cooling the coil end, and flows into the crank chamber 19.
[0149]
Since the stator of the motor 2 is press-fitted into the casing body 5a, the refrigerant mainly flows through the gap between the stator and the rotor. Therefore, the motor 2 can be efficiently cooled.
[0150]
The motor chamber 18 and the crank chamber 19 are partitioned by a partition plate 5c, and a plurality of through holes 17 (17a, 17b) are formed in the partition plate 5c. It flows into the motor chamber 18.
[0151]
However, most of the through holes 17b on the bottom side of the plurality of through holes 17 are closed by the lubricating oil 15, so that the refrigerant mainly flows into the crank chamber 19 through the through holes 17a on the piston 41 side. I do.
[0152]
Therefore, the refrigerant flows in the crank chamber 19 along the side of the piston 41 having a higher temperature than the bottom side, and also flows while cooling the first-stage compression section 11b having a higher temperature than the first-stage compression section 11a.
[0153]
As a result, the motor 2 can be efficiently cooled, and the deterioration of the insulation characteristics can be effectively suppressed. In addition, since the rear piston 41b having a higher temperature than the front piston 41a is cooled first, the compression efficiency due to the temperature is reduced. The compression efficiency in the latter compression unit 11b, where the decrease in the compression ratio is large, is improved.
[0154]
Further, since the pressure in the crank chamber 19 and the like is close to the pressure in the pre-stage discharge chamber 52, the differential pressure between the pressure in the crank chamber 19 and the like and the pressure in the compression chamber 42 becomes small, thereby reducing the motor load and driving. It is possible to suppress torque imbalance.
[0155]
In FIG. 16, the intercooler 70 is provided in the refrigerant introduction pipe 74. This is provided taking into consideration that if the temperature of the refrigerant from the pre-stage discharge chamber 52 is high, the cooling of the motor 2 and the like may not be performed efficiently. In the case where the cooling of 2 can be sufficiently performed, it is apparent that a configuration without the intercooler 70 may be adopted as shown in FIG.
[0156]
Also, if the temperature of the refrigerant that has cooled the motor 2 and the like is high, the compression efficiency in the latter-stage compression section 11b may decrease. In such a case, as shown in FIG. 18 and FIG. The tube 75 may be provided with a second intercooler 76.
[0157]
FIG. 18 shows a case where the first intercooler 70 is provided in the refrigerant introduction pipe 74 and the second intercooler is provided in the refrigerant return pipe 75. FIG. 19 shows a case where the second intercooler 76 is provided only in the refrigerant return pipe 75.
[0158]
With the above configuration, cooling of the motor 2 can be simultaneously performed while reducing the load on the connecting rod 26, and the service life of the connecting rod 26 and the like can be improved, and the characteristic deterioration of the motor 2 can be improved, thereby improving the reliability.
[0159]
Next, a fourth embodiment of the present invention will be described with reference to the drawings. Note that the same components as those of the above-described embodiments are denoted by the same reference numerals, and description thereof will be appropriately omitted.
[0160]
In the above embodiment, the refrigerant in the upstream discharge chamber 52 is guided to the motor chamber 18, and the motor 2 is cooled by the refrigerant.
[0161]
However, the present invention is not limited to such a configuration. For example, a liquefied or liquefied refrigerant may be guided to the motor chamber 18 and cooled in a refrigeration circuit as shown in FIG. .
[0162]
FIG. 20 is a diagram showing such a configuration. In FIG. 20, the bypass pipe 77 and the refrigerant supply path switch 78 shown in FIG. 11 are not provided, but it is to be noted in advance that the present invention may have such a configuration.
[0163]
In FIG. 20, a refrigerant pipe between the first heat exchanger 80 and the decompression device 81 and a liquid refrigerant introduction pipe 85 that communicates with the motor chamber 18 are connected to an end of the liquid refrigerant introduction pipe 85 to spray the refrigerant. A refrigerant return pipe 75 connected to the nozzle 86 and the crank chamber 19 and returning the refrigerant in the crank chamber 19 to the upstream suction chamber 51 is provided.
[0164]
FIG. 20 shows a configuration in which the heat liquefied in the first heat exchanger 80 is extracted and injected into the compressor 1 by extracting and using the heat from the first heat exchanger 80. However, the first heat exchanger 80 may utilize cold heat, and in such a case, the refrigerant radiates and liquefies in the second heat exchanger 82.
[0165]
Therefore, when utilizing the cold heat in the first heat exchanger 80, the refrigerant is extracted from the refrigerant pipe between the second heat exchanger 82 and the pressure reducing device 81 and injected into the compressor 1.
[0166]
The nozzle 86 is provided near the coil end (the end of the stator or the rotor) of the motor 2 so that the refrigerant blows on the coil end.
[0167]
Further, the end of the refrigerant return pipe 75 on the side of the crank chamber 19 is provided at a position where the lubricating oil 15 discharged from the lubricating oil return passage 31 does not easily adhere, and at a position close to the piston 41.
[0168]
In FIG. 20, the refrigerant return pipe 75 is provided to return the refrigerant in the crank chamber 19 to the front suction chamber 51. However, the refrigerant that has cooled the motor 2 and the like and has become higher in temperature is supplied to the front suction chamber 51. Then, the temperature of the refrigerant in the pre-stage suction chamber 51 rises and expands, and the amount of refrigerant compressed in the pre-stage compression unit 11a decreases, so that the compression efficiency may be reduced.
[0169]
In such a case, a method of returning the refrigerant that has cooled the motor 2 and the like to the second-stage suction chamber 53 is possible. For example, a configuration is conceivable in which the communication section 73 communicates the front discharge chamber 52, the rear suction chamber 53, and the crank chamber without providing the refrigerant return pipe 75.
[0170]
When the heat is used in the refrigeration circuit (when the heat utilization device is a heater or a water heater), the refrigerant from the compressor 1 passes through the first heat exchanger 80 via the four-way valve 83. Exchange heat with the heat utilization equipment side.
[0171]
In this heat exchange, the refrigerant releases heat and liquefies or liquefies, and then is supplied to the decompression device 81 to be decompressed. The second heat exchanger 82 exchanges heat with the outside air and evaporates. Then, the flow returns to the compressor 1 via the four-way valve 83.
[0172]
Since carbon dioxide is used as the refrigerant, the refrigerant that has undergone heat exchange in the first heat exchanger 80 is not in a condensed state as in a conventional HFC refrigerant and the like, and cannot be distinguished between a liquid and a gas. It is in a critical state. However, the refrigerant that has undergone heat exchange in the first heat exchanger 80 is in a state closer to a liquid than a gas or a state in which a part of the refrigerant is condensed, and thus is described as a liquefied refrigerant in this specification.
[0173]
On the other hand, when using the cold heat in the refrigeration circuit (when the heat utilization device is a cooling machine or a showcase), the refrigerant from the compressor 1 passes through the first heat exchanger 80 via the four-way valve 83. Exchange heat with outside air.
[0174]
In this heat exchange, the refrigerant releases heat and liquefies or liquefies, and then is supplied to the decompression device 81 to be decompressed. The first heat exchanger 80 exchanges heat with the heat utilization device side and evaporates. Then, the flow returns to the compressor 1 via the four-way valve 83.
[0175]
With the above configuration, the pressure in the crank chamber 19 and the like becomes close to the pressure in the pre-stage discharge chamber 52 by the communication portion 73, and the differential pressure between the pressure in the crank chamber 19 and the pressure in the compression chamber 42 becomes small. The inconvenience of applying a large load to the sliding portions of the main journal 22, the sub-journal 23, and the connecting rod 26 can be prevented, and an increase in motor load and an imbalance in drive torque can be suppressed.
[0176]
Further, the refrigerant extracted from the refrigeration circuit by the liquid refrigerant introduction pipe 85 is sprayed toward the coil end by the nozzle 86 to cool the coil end, and thereafter flows through the gap between the stator and the rotor. To cool the stator and the rotor.
[0177]
It is preferable that the refrigerant extracted from the refrigeration circuit is substantially completely condensed by being sprayed from the nozzle 86. However, when the temperature of the refrigerant supplied to the nozzle 86 is high, the refrigerant is sprayed from the nozzle 86. It is assumed that they do not completely condense even if they are performed.
[0178]
In such a case, as shown in FIG. 21, a capillary tube 87 may be provided in the liquid refrigerant introduction pipe 85 so that heat is released and reduced in pressure, and the liquid refrigerant is substantially completely condensed when sprayed from the nozzle 86.
[0179]
As described above, in addition to the effects described in the embodiments, the reliability of the motor 2 and the piston 41 can be more efficiently cooled so that the reliability can be improved.
[0180]
【The invention's effect】
As described above, according to the present invention, the refrigerant is carbon dioxide, and the bypass pipe that connects the upstream compression section and the downstream compression section, and is connected in parallel with the bypass pipe. The intercooler that dissipates the flowing refrigerant and the refrigerant compressed in the pre-stage compression section may be supplied to the post-stage compression section via a bypass pipe, or supplied to the post-stage compression section via an intercooler. With the provision of the refrigerant supply path switching device for switching whether or not to perform the compression, an optimal compression method can be selected according to the refrigerant temperature and the like required in the refrigeration circuit.
[Brief description of the drawings]
FIG. 1 is a detailed sectional view of a semi-hermetic type multi-stage compressor applied to the description of each embodiment of the present invention.
FIG. 2 is a sectional view taken along the line AA in FIG.
FIG. 3 is a top view of the sealing material.
FIG. 4 is a partial cross-sectional view of a sealing material on which full beads are formed.
FIG. 5 is a partial cross-sectional view of a sealing material on which a half bead is formed.
FIG. 6 is a view for explaining a difference in the number of piston rings mounted between a first-stage compression unit and a second-stage compression unit.
FIG. 7 is a view for explaining the swing of a piston.
FIG. 8 is a schematic sectional view of a piston provided with a surface hardened portion.
FIG. 9 is a schematic cross-sectional view when a wear-resistant portion is provided on a connecting rod.
FIG. 10 is a diagram showing a configuration of an intercooler.
FIG. 11 is a refrigeration circuit diagram when the supply path of the refrigerant to be supplied from the first-stage compression section to the second-stage compression section is changed according to the type of the heat utilization device.
FIG. 12 is a schematic configuration diagram of a compressor in a case where a communication portion is formed in a casing to communicate a crank chamber and the like with a discharge chamber at a preceding stage.
FIG. 13 is a view replacing FIG. 12 when the diameter of the connecting portion is changed in the middle.
FIG. 14 is a diagram instead of FIG. 12 in a case where a communication section is formed by pipe-connecting a crank chamber or the like and an upstream discharge chamber to form a communication section.
FIG. 15 is a view instead of FIG. 12 in a case where a communication portion is formed in a casing to communicate a crank chamber or the like with a rear suction chamber.
FIG. 16 is a schematic configuration diagram of a compressor when a refrigerant from a first-stage compression section is guided to a motor room via an intercooler.
FIG. 17 is a schematic configuration diagram of a compressor in place of FIG. 16 in a case where refrigerant from a first-stage compression section is directly introduced into a motor chamber.
FIG. 18 is a schematic configuration diagram of a compressor in a case where refrigerant from a first-stage compression section is guided to a motor chamber via a first intercooler, and refrigerant in a crank chamber is returned to a second-stage compression section via a second intercooler. It is.
FIG. 19 is a schematic configuration diagram of a compressor in a case where refrigerant from a first-stage compression section is directly guided to a motor chamber, and refrigerant in a crank chamber is returned to a second-stage compression section via a second intercooler.
FIG. 20 is a schematic configuration diagram of a compressor when liquid refrigerant or liquid refrigerant extracted from a refrigeration circuit is guided to a motor chamber.
FIG. 21 is a schematic configuration diagram of a compressor in a case where liquid refrigerant or liquid refrigerant extracted from a refrigeration circuit is guided to a motor chamber via a capillary tube.
FIG. 22 is a diagram showing a schematic configuration of a semi-hermetic type multi-stage compressor applied to description of a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Semi-hermetic type multi-stage compressor 2 Motor 3 Power conversion means 4 Compression means 5 Casing 5h Cylinder head 11 (11a, 11b) Compression part 13 Seal material 18 Motor room 19 Crank room 25 (25a, 25b) Crank 26 (26a, 26b) ) Connecting rod 35 Metal gasket 36 Elastic sheet gasket 37 (37a, 37b) Bead 40 (40a, 40b) Cylinder 41 (41a, 41b) Piston 42 (42a, 42b) Compression chamber 46 Piston ring 47 Surface hardened part 49 Wear resistant part 51 front suction chamber 52 front discharge chamber 53 rear suction chamber 54 rear discharge chamber 70 intercooler 73 communication part 74 refrigerant introduction pipe 75 refrigerant return pipe 76 second intercooler 77 bypass pipe 78 refrigerant supply path switcher 80 first heat exchange Device 81 depressurizing device 82 second heat exchanger 83 4 The valve 85 liquid refrigerant inlet pipe 86 nozzle 87 capillary tube

Claims (2)

A motor that generates rotational power, a power conversion unit that converts the rotational power into reciprocating power, and a compression unit that includes a plurality of compression units that reciprocate by the reciprocating power from the power conversion unit and compress the refrigerant. A plurality of casing members are assembled in a hermetically sealed state, and the casing includes a casing for accommodating the motor, power conversion means and compression means, and the refrigerant compressed by the compression section on the front stage side is further compressed by the compression section on the rear stage side. In a semi-hermetic multistage compressor that compresses and discharges,
The refrigerant is carbon dioxide, and
A bypass pipe connecting the compression section on the front stage side and the compression section on the rear stage side,
An intercooler connected in parallel with the bypass pipe to radiate the flowing refrigerant;
Refrigerant supply for switching between supplying the refrigerant compressed in the first-stage compression section to the second-stage compression section via the bypass pipe or supplying the second-stage compression section to the second-stage compression section via the intercooler. A semi-hermetic multi-stage compressor comprising a road switcher. 2. The semi-hermetic multistage compressor according to claim 1, wherein the intercooler is formed by press-fitting a plurality of fins into a pipe at predetermined intervals.

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