JP2000018154A - Reciprocating compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the excessive temperature rise in the bores at compression and eliminate the problem of the deterioration of the lubricant and seizing. SOLUTION: In a cylinder block 10, continuous cavities 50 are provided at the periphery of each bore 10a. To the cavities 50 returning refrigerant (cooling medium) from outside is introduced through an intake port 50. The returning refrigerant passes the cavities 50 and then leads to the intake chamber through communication holes. When the returning refrigerant passes the cavities 50, heat exchange between each of the bore 10a at high temperature and the returning refrigerant in the cavities 50 effectively restrains the temperature in the bores 10a at compression from increasing excessively. Further, when the refrigerant is returned, depriving heat of vaporization from the compressed refrigerant when the liquid particle in the returning refrigerant evaporates, contributes to this effective restriction of the temperature in the bores 10a at compression from increasing excessively. Even if the refrigerant is returned, it is not compressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor, and more particularly, to a reciprocating compressor capable of suppressing an excessive rise in temperature in a bore. INDUSTRIAL APPLICABILITY The reciprocating compressor of the present invention can be suitably used for a cooling device for vehicle air conditioning or the like.

[0002]

2. Description of the Related Art Conventionally, as a reciprocating compressor (hereinafter simply referred to as a "compressor") provided for a cooling device for vehicle air conditioning, a cylinder block having a plurality of bores arranged side by side and corresponding to the bores A valve plate having a suction hole and a discharge hole formed therethrough, a suction chamber and a discharge chamber are defined, and a housing closing an outer end of the cylinder block, and a suction interposed between the cylinder block and the valve plate A valve, a discharge valve interposed between the housing and the valve plate, and a piston that reciprocates in the bore, compresses refrigerant sucked from the suction chamber, and discharges the refrigerant to the discharge chamber. It has been known.

In such a compressor, the low-temperature and low-pressure refrigerant gas returned to the suction chamber from the outside by the piston reciprocating in the bore is drawn into the bore and compressed, and then becomes the high-temperature and high-pressure refrigerant gas. And discharged into the discharge chamber.

[0004]

In such a compressor, when the refrigerant gas is compressed in the bore, the temperature of the refrigerant gas increases with an increase in pressure. At this time, if the temperature in the bore becomes too high, not only does the work required for compression increase, but also the problems of deterioration and seizure of the lubricating oil contained in the refrigerant gas tend to occur.

[0005] The above problem is particularly caused by a cooling device that operates so that the high-pressure side pressure (discharge pressure of the compressor) of the closed circuit constituting the cooling device becomes the supercritical pressure of the refrigerant. Device ”)).
That is, in the compressor of the cooling device of the supercritical cycle, the refrigerant gas is compressed to a pressure exceeding the critical pressure of the refrigerant. For example, when carbon dioxide having a critical pressure of about 7.35 MPa is used as a refrigerant, the compressor uses 10 MPa.
The refrigerant gas is compressed to a pressure of about a. When a CFC-based refrigerant is used as the refrigerant, in other words, a cooling device that operates at a pressure lower than the critical pressure of the refrigerant used for both the discharge pressure and the suction pressure (hereinafter, appropriately referred to as a “subcritical cycle cooling device”). In, the discharge pressure of the compressor is about 1 to 3 MPa, and the discharge pressure of the compressor in the supercritical cycle cooling device is extremely higher than that of the subcritical cycle cooling device. For this reason, in the compressor in the cooling device of the supercritical cycle, when the refrigerant gas is compressed in the bore, the temperature of the compressed refrigerant (discharge gas) in the bore is increased by the increase in the discharge pressure, and the lubricating oil Deterioration and seizure problems are likely to occur.

The present invention has been made in view of the above circumstances, and suppresses an excessive increase in the bore temperature during compression (compressed refrigerant temperature and discharge gas temperature) to prevent deterioration and seizure of lubricating oil. Solving the problem is a technical problem to be solved.

[0007]

According to a first aspect of the present invention, there is provided a reciprocating compressor including a cylinder block having a plurality of bores arranged side by side, and a valve having a suction hole and a discharge hole corresponding to the bores. A plate, a suction chamber and a discharge chamber are defined, a housing closing the outer end of the cylinder block through the valve plate, and a reciprocating motion in the bore to compress the refrigerant sucked from the suction chamber. A reciprocating compressor including a piston that discharges into the discharge chamber, wherein the cylinder block has a cavity around each of the bores, and the cavity has a cooling medium for cooling the inside of each of the bores. Are allowed to pass through.

In this compressor, a hollow portion is provided around each bore of the cylinder block, and a cooling medium passes through the hollow portion. For this reason, it is possible to suppress the temperature inside the bore during compression from becoming excessively high due to heat exchange between the inside of the high-temperature bore and the cooling medium in the cavity. Therefore, it is possible to suppress the deterioration of the lubricating oil and the occurrence of seizure due to the excessively high temperature in the bore at the time of compression.

Further, the weight of the cylinder block can be reduced by the weight of the hollow portion provided in the cylinder block, and the weight of the entire compressor can be reduced. (2) In the reciprocating compressor according to the second aspect, in the reciprocating compressor according to the first aspect, the cavity communicates with a suction port for sucking a return refrigerant from the outside and the suction chamber. The return refrigerant is once introduced into the cavity, and thereafter is led out to the suction chamber, and the return refrigerant is used as the cooling medium.

In a cooling system comprising a compressor, a radiating heat exchanger, a throttling means, and a heat absorbing heat exchanger (evaporator), a refrigeration circuit is provided by evaporating pressure (evaporating temperature) in the evaporator. If the refrigerant gas containing the liquid particles returns to the compressor (liquid back) and the liquid is compressed in the bore, the flow resistance due to the liquid increases, and the discharge valve and the like may be damaged.

[0011] In this respect, in this compressor, the return refrigerant is once introduced into cavities provided around the respective bores of the cylinder block, and thereafter is discharged to the suction chamber. For this reason, even if the refrigerant containing the liquid particles returns to the compressor due to liquid back, the returned refrigerant containing the liquid particles is heated by the high-temperature bore while passing through the cavity, so that the refrigerant in the refrigerant gas is heated. After the liquid particles evaporate and become completely evaporated superheated steam, they are led to the suction chamber. Therefore, liquid compression is not performed in the bore, and damage to the discharge valve and the like due to liquid compression can be prevented.

Further, while the return refrigerant passes through the cavity, heat exchange occurs between the high-temperature compressed refrigerant in the bore and the low-temperature return refrigerant in the cavity, and when the liquid particles in the return refrigerant evaporate. Since the heat of vaporization is removed from the compressed refrigerant, it is of course possible to effectively prevent the temperature in the bore from excessively increasing during compression. (3) A reciprocating compressor according to claim 3 is characterized in that, in the reciprocating compressor according to claim 1 or 2, the discharge gas is discharged at a supercritical pressure of the refrigerant.

When the compressor discharges the discharge gas at the supercritical pressure of the refrigerant, the temperature of the compressed refrigerant (discharge gas) in the bore increases as much as the discharge pressure increases, as described above. However, as described above, by allowing the cooling medium to pass through the cavity around each bore of the cylinder block, an excessive rise in the bore temperature is effectively suppressed as described above. be able to. Therefore, even when the compressor discharges the discharge gas at the supercritical pressure of the refrigerant, it is possible to effectively suppress the deterioration of the lubricating oil and the occurrence of seizure due to the excessive rise in the bore temperature during compression. It becomes possible.

As will be described later, a supercritical cycle cooling device includes a compressor, a gas cooler as a heat exchanger for heat dissipation, an expansion valve as a throttling means, and an evaporator as a heat exchanger for heat absorption. And a closed circuit in which an accumulator as a gas-liquid separator is connected in series. When the return refrigerant returns from the accumulator to the compressor in this manner, liquid back is likely to occur, and the discharge valve and the like are easily damaged by liquid compression.

In this regard, as described above, once the return refrigerant is introduced into the cavity around each bore of the cylinder block, the liquid particles in the return refrigerant can be completely evaporated in the cavity. Therefore, even when the compressor discharges the discharge gas at the supercritical pressure of the refrigerant, liquid compression is not performed in the bore, and it is possible to reliably prevent damage to the discharge valve and the like due to liquid compression. Become.

Further, since the discharge pressure is increased in the compressor applied to the cooling device of the supercritical cycle, the bore diameter can be reduced. However, since the swash plate element and the like require a certain outside diameter to reciprocate the piston with a certain stroke or more, the cylinder block also needs a certain outside diameter in accordance with this. For this reason, in the compressor applied to the cooling device of the supercritical cycle, there is a problem that the wall thickness of the cylinder block around the bore is increased by the smaller bore diameter, and the weight of the cylinder block is increased.

In this regard, as described above, the weight of the cylinder block can be reduced by the weight of the hollow portion provided in the cylinder block, so that the compressor discharges the discharge gas at the supercritical pressure of the refrigerant. Even so, the weight of the entire compressor can be reduced. (4) The reciprocating compressor according to claim 4 is the reciprocating compressor according to claim 3, wherein the refrigerant is carbon dioxide.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. (Embodiment 1) A compressor 1 shown in FIG. 1 is a cooling device for air conditioning of a vehicle, which is used for a cooling device of a supercritical cycle. That is, in this cooling device, the compressor 1, a gas cooler as a heat exchanger for heat dissipation (not shown), an expansion valve as a throttle means, an evaporator as a heat exchanger for heat absorption, and an accumulator as a gas-liquid separator are connected in series. Compressor discharge pressure (high pressure side of the circuit)
Operates to reach the supercritical pressure of the refrigerant circulating in the circuit. Then, carbon dioxide (CO ₂ ) is used as a refrigerant. In addition, as a refrigerant, carbon dioxide (CO
₂ ) Besides ethylene (C ₂ H ₄ ) and deborane (B ₂
H ₆ ), ethane (C ₂ H ₆ ), nitric oxide and the like can also be used.

In the compressor 1, the cylinder block 10
A front housing 11 is joined to the front end of the cylinder block 10, and a rear housing 13 is joined to the rear end of the cylinder block 10 with the valve plate 12 and the like interposed therebetween. Front housing 1
A drive shaft 15, one end of which extends from the front housing 11 and is fixed to an armature of an electromagnetic clutch (not shown), is housed in a crank chamber 14 formed by the cylinder block 1 and the cylinder block 10. It is rotatably supported by a shaft sealing device and a radial bearing provided between the cylinder block 11 and the cylinder block 10. A thrust bearing and a leaf spring (not shown) are interposed between the other end of the drive shaft 15 and the valve plate 12 or the like. The cylinder block 10 is provided with six bores 10 a at positions surrounding the drive shaft 15, and each of the bores 10 a accommodates a piston 16.

In the crank chamber 14, a rotor 18 is fixed to the drive shaft 15 through a thrust bearing between the rotor 18 and the front housing 11 so as to be able to rotate synchronously with the drive shaft 15.
Behind the rotor 18, the swash plate 2 is rotated by a hinge mechanism 19.
0 is moored so as to be able to rotate synchronously with the rotor 18. A sleeve 21 is slidably provided on the peripheral surface of the drive shaft 15 in the crank chamber 14.
The rotating swash plate 20 is swingably moored to a pivot 21a protruding from the shaft 21a. The rotary swash plate 20 has a thrust bearing 22
The swinging swash plate 23 is moored through the
A non-illustrated detent pin slidable only in the axial direction in the detent groove 11 a of the front housing 11 is fixed to the front housing 3. A rod 24 is moored between the swash plate 23 and each of the pistons 16 so that each of the pistons 1
Numeral 6 can reciprocate in each bore 10a in accordance with the inclination angle of the swash plate 23.

A pressing spring 25 is provided between the sleeve 21 and a circlip fixed to the drive shaft 15 on the cylinder block 10 side. Then, the rotary swash plate 20 can be brought into contact with the rotor 18 by the pressing spring 25, so that the swinging swash plate 23 is maintained at the maximum inclination angle at the time of starting or the like. Further, the swing swash plate 23 can be maintained at the minimum inclination angle in a state where the pressing spring 25 is most contracted.

In the rear housing 13, a discharge chamber 26 is formed at the center side, and a suction chamber 27 is formed outside the discharge chamber 26. Each of the compression chambers and the discharge chambers 2 formed between the end faces of the pistons 16 and the bores 10a
6 is communicated with each of the discharge holes 12a (see FIG. 3) formed in the valve plate 12, and each of the discharge holes 12a is
The discharge valve 43 whose opening is regulated by the retainer 26a on the sixth side can be opened and closed. The respective compression chambers and the suction chamber 27 are communicated by respective suction holes 12b (see FIG. 3) formed in the valve plate 12, and each suction hole 12b can be opened and closed by a suction valve 44 on each compression chamber side. Has been made.

Further, a bleed passage (not shown) for communicating the crank chamber 14 with the suction chamber 27 is formed in the rear housing 13, the valve plate 12, the cylinder block 10, and the like. An air supply passage 29 is formed as a control passage communicating with the chamber 14, and the control valve 3 is provided in the rear housing 13 in the middle of the air supply passage 29.
0 is equipped.

The control valve 30 is provided with a suction pressure chamber 31 and a discharge pressure chamber 32 facing each other.
Through the suction chamber 27 and the discharge pressure chamber 32 through the through hole 34.
And are communicated with the discharge chamber 26 through the respective holes.
The suction pressure chamber 31 has an atmospheric pressure chamber 3 disposed at the center.
The bellows 36 is provided to extend and retract so as to surround the bellows 5, and the bellows 36 is constantly urged in the extending direction (toward the discharge pressure chamber 32) via a spring 37. On the other hand, the discharge pressure chamber 32 is provided with a valve hole 38 at one end close to the suction pressure chamber 31, and a port 39 defined and connected to the valve hole 38 is connected to the crank chamber 14 through the air supply passage 29. Are in communication. A base end of a valve rod 40 is connected to the bellows 36 and extends in the direction of the discharge pressure chamber 32.
And through the valve hole 38 so as to reach the inside of the discharge pressure chamber 32. A valve body 41 is attached to the distal end of the valve rod 40 so as to face the valve hole 38. The valve body 41 is configured to be capable of opening and closing through expansion and contraction of the bellows 36, and is connected to the discharge pressure chamber 32. It is always urged in the direction of the valve hole 38 (close direction) by the interposed spring 42. Therefore, when the suction chamber pressure introduced into the suction pressure chamber 31 becomes lower than the set value, the valve rod 40 advances with the extension of the bellows 36 to open the valve body 41, and the port 39 and the supply port are supplied from the valve hole 38. The discharged refrigerant gas is supplied to the crank chamber 14 via the air passage 29.

Therefore, in this compressor, the drive shaft 15
Is converted into the forward and backward swing of the swinging swash plate 23 through the rotating swash plate 20, and the refrigerant gas sucked into the bore 10a from the suction chamber 27 by the piston 16 reciprocating in the bore 10a is converted. It is discharged to the discharge chamber 26 while being compressed. The stroke of the piston 16 and the tilt angle of the swash plate 23 change according to the pressure difference between the crank chamber pressure and the suction chamber pressure controlled by the control valve 30 based on the cooling load,
The discharge capacity is controlled.

Here, in the compressor 1, in the cylinder block 10, a continuous hollow portion 50 is provided around each bore 10a over the entire circumference of the bore 10a. The hollow portion 50 extends from the rear end surface of the cylinder block 10 to the vicinity of the front end portion of the cylinder block 10 with the same cross-sectional shape as shown in FIG. 2 while leaving the circular pipe wall 10b around each bore 10a (FIG. 1). In the vicinity of the front end of the hollow portion 50, a suction port 51 extending in a direction substantially perpendicular to the axis of the bore 10a is opened, and at the rear end of the hollow portion 50, the shaft is attached to the valve plate 12 or the like. The suction chamber 27 penetrates in the center direction.
A communication hole 52 communicating with the opening is formed. Suction port 51
Is connected via a pipe to an accumulator constituting a refrigeration circuit of the cooling device. The discharge chamber 26 is connected via a pipe to a gas cooler constituting a refrigeration circuit of the cooling device.

Thus, in the compressor 1, the refrigerant returned from the accumulator is used as a cooling medium as the suction port 5
1, is once introduced near the front end of the hollow portion 50, then flows around the bores 10 a toward the rear end while flowing around the bores 10 a, and flows out to the suction chamber 27 through the communication hole 52. Is configured. In the compressor 1 configured as described above, when the rotation of the engine (not shown) as a drive source is transmitted to the drive shaft 15 by the electromagnetic clutch, the rotation of the drive shaft 15 synchronizes with the rotor 18 to rotate the swash plate. 20 is rotated at a predetermined inclination angle, and only the swinging motion of the rotary swash plate 20 is transmitted to the swing swash plate 23. Therefore, the piston 16 reciprocates in the cylinder 10a via the rod 24 by the swinging motion of the swinging swash plate 23. Thereby, the refrigerant in the suction chamber 27 is compressed in the compression chamber, and then discharged to the discharge chamber 26.

At this time, in the cooling device according to the present embodiment using carbon dioxide as the refrigerant, the compressor discharges the discharge gas at the supercritical pressure of the refrigerant (about 10 MPa).
In such a case, since the discharge pressure is particularly high, the temperature of the compressed refrigerant (discharge gas) in the bore 10a also increases as much as the discharge pressure increases, so that problems such as deterioration of lubricating oil and seizure easily occur. There is.

In this regard, in the compressor 1 of the present embodiment, as described above, the return refrigerant as a cooling medium is introduced into the hollow portion 50 around each of the bores 10a of the cylinder block 10. The heat exchange between the high-temperature bores 10a and the return refrigerant in the hollow portion 50 via the heat exchanger further removes the heat of vaporization from the compression refrigerant when the liquid particles in the return refrigerant evaporate in the case of liquid back, thereby compressing the refrigerant. Time Bore 1
Excessive rise in the temperature in Oa can be effectively suppressed. Therefore, even when the compressor 1 discharges the discharge gas at the supercritical pressure of the refrigerant, the bore 1 during compression is
It is possible to effectively suppress the deterioration of the lubricating oil and the occurrence of seizure due to the temperature inside 0a being excessively high.

Further, in the cooling device of the supercritical cycle, since the refrigerant returns to the compressor 1 from the evaporator via the accumulator, liquid back tends to occur, and the discharge valve and the like are easily damaged by liquid compression. In the compressor 1, the return refrigerant is once introduced into the cavity 50 provided around each of the bores 10 a of the cylinder block 10, and then the communication holes 52 are formed.
Through the suction chamber 27. Therefore, even if the refrigerant containing the liquid particles returns to the compressor 1 due to the liquid back, the returned refrigerant containing the liquid particles remains in each of the bores 10a through the pipe wall 10b while passing through the cavity 50. The liquid particles in the refrigerant gas evaporate by being heated by the high-temperature compressed refrigerant, and the liquid particles are guided to the suction chamber 27 after being completely evaporated into superheated steam. Therefore, even when the compressor 1 discharges the discharge gas at the supercritical pressure of the refrigerant, the liquid is not compressed in the bore 10a, and it is possible to reliably prevent the discharge valve and the like from being damaged by the liquid compression. It becomes possible.

Further, in a compressor applied to a cooling device of a supercritical cycle, there has conventionally been a problem that the wall thickness of the cylinder block 10 around the bore 10a becomes thick and the weight of the cylinder block 10 increases. In this regard, in the compressor 1 of the present embodiment, the weight of the cylinder block 10 can be reduced by the weight of the hollow portion 50 provided in the cylinder block 10, and the overall weight of the compressor 1 can be reduced. .

The diameter, number, and location of the communication holes 52 may be appropriately set in consideration of the suction pressure loss and the like. (Embodiment 2) In a compressor 1 of Embodiment 2, as shown in FIG. 3, a partial cross-sectional view in which a main part is enlarged is formed on a rear end surface of a cylinder block 10 by an annular seal portion surrounding each bore 10a. A gasket 45 is provided as a seal member capable of ensuring the sealing performance of each bore 10a.

That is, the gasket 45 is sandwiched between the cylinder block 10 and the suction valve 44 disposed on the front end face of the valve plate 12. The gasket 45 includes a disk-shaped metal plate 46 and elastic rubber films 47 and 48 fixed to both end surfaces of the metal plate 46, respectively. As shown in FIG. Bore 10
The six through-holes 45a having the same size as the bore 10a are respectively provided at positions corresponding to a. In addition, six through holes 45 penetrated slightly outside between the through holes 45a.
b is a through hole for a bolt for fastening the cylinder block 10 and the rear housing 13 and the like. An annular bead portion 45c as an annular seal portion surrounding each bore 10a is formed around each through hole 45a. The annular bead portion 45c is formed by partially bending the metal plate 46 into a convex bead shape at a position corresponding to each circular tube wall 10b of the cylinder block 10.

The annular bead portion 45c is provided with a gasket 4
5 is about 0.2 mm in height and about 2 mm in width before being sandwiched between the cylinder block 10 and the suction valve 44. After the gasket 45 has been clamped between the cylinder block 10 and the suction valve 44 and assembled to the compressor 1, the projecting tip of the annular bead portion 45c has a full circumference around the front end face of the suction valve 44 as a clamping surface. Is slightly crushed by being pressed. In this sandwiched state, the annular bead portion 4
The elastic rubber film 47 on the side where 5c protrudes and covers the protruding tip of the annular bead portion 45c is
It is compressed and held between the suction valve 44 and the metal plate 46 over the entire circumference.

The other structure is the same as that of the first embodiment. Therefore, in the compressor 1 of the present embodiment, each annular bead 45c of the gasket 45 disposed corresponding to each circular pipe wall 10b surrounds the periphery of each bore 10a, and each annular bead 45c is By being pressed against the front end surface of the suction valve 44 over the entire circumference, the elastic rubber film 47 covering the projecting tip of each annular bead portion 45c is compressed and sandwiched between the suction valve 44 and the metal plate 46 over the entire circumference. I have. Therefore, in the compressor 1, the sealing performance of each bore 10 a can be ensured by the annular bead portion 45 c, and each of the bores 10 a passes through the space between the circular pipe wall 10 b of the cylinder block 10 and the suction valve 44. It is possible to suppress high-pressure refrigerant gas from leaking into the cavity 10a.

Therefore, even when the compressor 1 discharges the discharge gas at the supercritical pressure of the refrigerant, the performance of the compressor 1 can be suppressed from being deteriorated due to the leakage of the refrigerant gas from around the bore 10a. . (Embodiment 3) As shown in FIG. 5, the compressor 1 of Embodiment 3 has a partial cross-sectional view in which a main part is enlarged. An O-ring 49 is provided as a seal member capable of ensuring the sealing performance of each bore 10a.

That is, in the compressor 1, each bore 10a is provided between the cylinder block 10 and the suction valve 44.
An O-ring 49 is provided for each of the bores 10a so as to surround the bore. Specifically, O-rings 49 are respectively provided in the annular grooves 10c formed on the rear end face of each of the cylindrical pipe walls 10b of the cylinder block 10 so as to surround the respective bores 10a. Then, the valve plate 12 and the suction valve 44 are connected to the cylinder block 10 and the rear housing 13.
Each O-ring 49 is sandwiched between the
The end face of the O-ring 49 on the suction valve 44 side is pressed against the suction valve 44 over the entire circumference. The suction valve 44
The end surface of the O-ring 49 on the side functions as an annular seal portion.

Other configurations are the same as those in the first embodiment. Therefore, in the compressor 1 as well, in the same manner as in the second embodiment, the sealing performance of each bore 10a can be secured by the O-ring 49, and the cylindrical wall 10 of the cylinder block 10 can be secured.
b and the suction valve 44, it is possible to suppress the leakage of the high-pressure refrigerant gas from each bore 10a to the cavity 10a, and the compressor 1 discharges the discharge gas at the supercritical pressure of the refrigerant. Even in this case, it is possible to suppress a decrease in the performance of the compressor 1 due to leakage of the refrigerant gas from around the bore 10a.

In the above-described embodiment, an example has been described in which the return refrigerant from the accumulator is introduced into the cavity 50 as a cooling medium, but the present invention is not limited to this. For example, the outside air may be introduced into the cavity 50 as a cooling medium to cool the bore 10a. In this case, in the first embodiment, the suction port 51 opened near the front end of the cavity 50 is opened to the outside air to serve as an outside air introduction port, and the communication hole 52 is eliminated.
It is sufficient that an outside air discharge port is provided near the rear end so that outside air can pass through the cavity 50. In this case, the return refrigerant from the accumulator is directly introduced into the suction chamber 27.
According to such an embodiment, it is possible to suppress the temperature inside the bore 10a from excessively rising due to heat exchange with the outside air passing through the cavity 50.

Although the above-described embodiment has been described with respect to an example in which the present invention is applied to a cooling device of a supercritical cycle using carbon dioxide as a refrigerant, the compressor of the present invention uses a subcritical cycle using a fluorocarbon-based refrigerant or the like as a refrigerant. It is needless to say that the present invention can be applied to the cooling device.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a reciprocating compressor according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a main part of the reciprocating compressor of the first embodiment.

FIG. 3 is a partially enlarged cross-sectional view in which main parts of a reciprocating compressor according to a second embodiment are enlarged.

FIG. 4 is a plan view of a gasket as a seal member according to the second embodiment.

FIG. 5 is a partially enlarged cross-sectional view in which main parts of a reciprocating compressor according to a third embodiment are enlarged.

[Explanation of symbols]

10 ... Cylinder block 10a ... Bore
12 Valve plate 12a Discharge hole 12b Suction hole 13
Rear housing 16 Piston 26 Discharge chamber 27
Suction chamber 50 ... Cavity part 51 ... Suction port 52 ...
Communication hole

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuo Murakami 2-1-1 Toyota-cho, Kariya-shi, Aichi F-term in Toyota Industries Corporation (reference) 3H003 AA03 AC03 BE09 CD01 3H076 AA06 BB05 BB17 CC20 CC46 CC83 CC94

Claims (4)

[Claims] 1. A cylinder block in which a plurality of bores are arranged side by side, a valve plate in which a suction hole and a discharge hole corresponding to the bore are penetrated, and a suction chamber and a discharge chamber are defined. A reciprocating compressor including a housing for closing an outer end of the cylinder block, and a piston for reciprocating in the bore, compressing refrigerant sucked from the suction chamber and discharging the refrigerant to the discharge chamber, A reciprocating compressor, wherein a hollow portion is provided around each of the bores in the cylinder block, and the hollow portion allows a cooling medium for cooling the inside of each of the bores to pass therethrough. 2. The cavity communicates with a suction port for sucking return refrigerant from the outside and the suction chamber, and is configured to once introduce the return refrigerant into the cavity and then to discharge the return refrigerant to the suction chamber. The reciprocating compressor according to claim 1, wherein the return refrigerant is used as the cooling medium. 3. The reciprocating compressor according to claim 1, wherein the discharge gas is discharged at a supercritical pressure of the refrigerant. 4. The reciprocating compressor according to claim 3, wherein the refrigerant is carbon dioxide.