WO2008066156A1 - Reciprocating compressor of refrigerating machine - Google Patents

Abstract

A reciprocating compressor of refrigerating machine that realizes inhibition of any temperature increase of discharged refrigerant and enhancing of refrigerant compression efficiency. The reciprocating compressor of refrigerating machine is one comprising housing (16) with cylinder bore (30); piston (32) capable of reciprocating motion in the cylinder bore (30), fitted in the cylinder bore (30); intermediate pressure chamber (68) disposed within the housing (16), into which a low-temperature refrigerant is led from gas-liquid separator (10) of refrigerating machine; and rotary valve (78) disposed between compression chamber (33) and the intermediate pressure chamber (68), wherein the rotary valve (78) rotates in conjunction with main shaft (34) of the compressor and, when the refrigerant is in the stage of compression within the compression chamber (33), opens so as to jet the low-temperature refrigerant from the intermediate pressure chamber (68) into the compression chamber (33).

Description

 Specification

 Reciprocating compressor for refrigerator

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a reciprocating compressor of a refrigerator, and more particularly, to a compressor suitable for a refrigerator included in an air conditioning system of an automobile.

 Background art

 [0002] This type of reciprocating compressor includes a cylinder block having a plurality of cylinder bores, a piston that is reciprocally inserted into each cylinder bore of the cylinder block, and forms a compression chamber in the cylinder bore. And a rotatable main shaft that reciprocates each piston within the corresponding cylinder bore. When the main shaft is rotated, the pistons reciprocate sequentially in the corresponding cylinder bores, and the reciprocating motion of such pistons is caused by the suction of refrigerant into the corresponding compression chamber through the compression of the refrigerant in the compression chamber. Then, a series of processes leading to the discharge of the compressed refrigerant from the compression chamber is repeatedly performed (Patent Document 1).

 Patent Document 1: Japanese Patent Laid-Open No. 2001-027177

 Disclosure of the invention

 Problems to be solved by the invention

[0003] An alternative chlorofluorocarbon gas called R134a is generally used for an air conditioning system of an automobile, that is, a refrigerant of its refrigerator. However, such alternative chlorofluorocarbons are very high V and have a global warming index (Global

 Specifically, the GWP of the alternative chlorofluorocarbon gas is about 1300. Therefore, the refrigerator of Patent Document 1 uses carbon dioxide (GWP) with a low GWP instead of the above-mentioned alternative chlorofluorocarbon as a refrigerant. CO) is used. In recent years, it has also been proposed to use a new alternative refrigerant having a low GPW, and this alternative refrigerant contains a double bond (for example, R1 234YF).

[0004] When the CO refrigerant is compressed by the compressor, the temperature of the refrigerant, that is, the discharge temperature of the refrigerant, is higher than when R134a is compressed by the compressor. Specifically, the CO refrigerant The discharge temperature exceeds 150 ° C and the heat load received by the compressor is large. On the other hand, when the above-mentioned new alternative refrigerant is compressed by the compressor, the discharge temperature of this refrigerant is suppressed to the same extent as in the case of R134a. However, a new alternative refrigerant containing a double bond is easily decomposed at the discharge temperature of the refrigerant because the double bond is likely to be released under high temperature use conditions. An object of the present invention is to provide a reciprocating compressor for a refrigerator that can suppress an increase in refrigerant discharge temperature and at the same time increase the compression efficiency of the refrigerant.

 Means for solving the problem

In order to achieve the above object, a reciprocating compressor of a refrigerator according to the present invention is fitted with a housing having a cylinder bore and a compression chamber formed in the cylinder bore, and in the cylinder bore. This reciprocating piston performs a series of processes including suction of refrigerant into the compression chamber, compression of suction refrigerant in the compression chamber, and discharge of compressed refrigerant from the compression chamber. When the refrigerant is supplied to the refrigerant circulation path of the refrigerator and placed in the housing and the housing, and the refrigerant is in the compression process, the intermediate refrigerant is introduced into the compression chamber from the refrigerant circulation path for a predetermined period. Preferably, the introduction device is lower than the temperature of the compressed refrigerant in the compression process, the introduction device having an intermediate refrigerant having a pressure higher than the pressure of the compressed refrigerant in the compression chamber. To introduce the intermediate refrigerant into the compression chamber having a degree.

[0006] Specifically, the introduction device is formed in the housing and is supplied with an intermediate pressure chamber to which the intermediate refrigerant is supplied from the refrigerant circulation path, a connection passage connecting the intermediate pressure chamber and the compression chamber, and the connection A valve that is provided in the passage and opens and closes the connection passage, and the connection passage is opened in a time zone until the pressure of the compressed refrigerant in the compression process reaches the pressure of the intermediate refrigerant in the intermediate pressure chamber. Including an opening valve.

 including.

[0007] According to the above-described reciprocating compressor, the valve is opened when the refrigerant is in the compression process in the compression chamber. Since the pressure of the intermediate refrigerant in the intermediate pressure chamber is higher than the pressure of the compressed refrigerant in the compression chamber at the timing when the valve is opened, the intermediate medium is injected into the compression chamber when the valve is opened. At this time, the temperature of the intermediate refrigerant is the compressed refrigerant in the compression chamber in the compression process. The compressed refrigerant in the compression chamber that is lower than the temperature of the refrigerant is cooled by being mixed with the intermediate refrigerant, so that the rise in the temperature of the refrigerant discharged from the compressor is suppressed. Refrigerants containing compounds with double bonds can be used, greatly contributing to the prevention of global warming. Also, when the refrigerant is in the compression process in the compression chamber, if the intermediate refrigerant is injected into the compression chamber, the compression efficiency of the compressed refrigerant can be increased, and the energy efficiency of the refrigerator is greatly improved.

 The valve described above is a rotary valve that is mechanically coupled to the main shaft and rotates integrally with the main shaft, or a rotary valve that is rotated by a motor independent of the main shaft, or an electromagnetic valve.

 Further, the compressor can further include a variable capacity mechanism that varies the discharge amount of the compressed refrigerant, and the variable capacity mechanism has a swash plate.

 Brief Description of Drawings

 [0008] Fig. 1 is a diagram showing an outline of a refrigerator.

 FIG. 2 is a cross-sectional view showing details of the compressor of FIG.

 FIG. 3 is a view showing a rotary valve of a modified example.

 FIG. 4 is a view showing an electromagnetic on-off valve.

 BEST MODE FOR CARRYING OUT THE INVENTION

[0009] The refrigerator of FIG. 1 is incorporated in an air conditioning system for an automobile and includes a circulation path 2 for the refrigerant. In this circulation path 2, a compressor 4, a condenser 6, a first expansion valve 8, a gas-liquid separator 10, a second expansion valve 12 and an evaporator 14 are sequentially interposed. The compressor 4 compresses and discharges the refrigerant, and the discharged refrigerant is supplied to the condenser 6 and circulates in the circulation path 2. Here, the circulation path 2 includes the discharge port of the compressor 4 or the high pressure region 2 from the 4d through the condenser 6 to the first expansion valve 8, and the gas-liquid separator 10 and the second expansion valve from the first expansion valve 8. 12 and evaporator 14

 H

 And a low-pressure region 2 that reaches the suction port 4s of the compressor 4 through.

 L

 FIG. 2 shows details of the compressor 4.

The compressor 4 is a variable capacity and reciprocating compressor, and includes a housing 16. The housing 16 has an end plate 18, a center casing 20 and a cylinder head 22 from the left side as viewed in FIG. 2, and the end plate 18, the center casing 20 and the cylinder head. 22 is integrally connected.

 The center casing 20 defines a crank chamber 24 therein, and the crank chamber 24 is disposed between the end plate 18 and the end wall of the center casing 20, that is, the cylinder block 26.

 Further, a compression unit 28 is disposed in the center casing 20, and the compression unit 28 will be described in detail below.

The cylinder block 26 has a plurality of cylinder bores 30 therein. These cylinder bores 30 are arranged at equal intervals around the axis of the cylinder block 26 and pass through the cylinder block 26. Pistons 32 are slidably fitted in the cylinder bores 30, and these pistons 32 form compression chambers 33 in the corresponding cylinder bores 30. On the other hand, a main shaft 34 is disposed in the crank chamber 24. The main shaft 34 is positioned coaxially with the axis of the cylinder block 26 and has an inner end and an outer end, respectively. The inner end of the main shaft 34 enters the cylinder block 26 and is supported by the cylinder block 26 through a bearing 36 so as to rotate freely. On the other hand, the outer end of the main shaft 34 protrudes outside the housing 16. That is, the main shaft 34 passes through the end plate 18 and is supported by the end plate 18 via the bearing 38 and the seal unit 40. The outer end of the main shaft 34 is connected to an automobile engine via a power transmission path (not shown). Therefore, when the driving force of the engine is transmitted from the engine to the main shaft 34, the main shaft 34 rotates in one direction.

A rotor 42 is attached to the main shaft 34, and the rotor 42 is disposed in the crank chamber 24. The rotor 42 rotates integrally with the main shaft 34 and is rotatably supported by the end plate 18 via a thrust bearing 44.

A swash plate 46 is disposed in the crank chamber 24, and this swash plate 46 surrounds the main shaft 34. The swash plate 46 and the rotor 42 are connected to each other via a link 48, and the link 48 allows the swash plate 46 to tilt with respect to the main shaft 34 that changes the inclination angle of the swash plate 46. Further, the swash plate 46 supports a swing plate 42 via a radial bearing 50 and a thrust bearing 52, and the rotation of the swing plate 54 is blocked by a rotation prevention mechanism (not shown! /). ! / The swing plate 54 described above is connected to each piston 32 via a piston rod 56. These screw rods 56 have ball joints 57a and 57b at both ends thereof. The ball joint 57a connects the swing plate 54 and the piston rod 56, and the ball joint 57b connects the piston rod 56 and the piston 32. Therefore, when the main shaft 34 is rotated, the rotation of the main shaft 34 is converted into a reciprocating motion of each piston 32 via the rotor 42, the swash plate 46, the swing plate 54 and the piston rod 56.

 As is apparent from FIG. 2, there is a gasket between the cylinder block 26 and the cylinder head 22.

 A valve plate 58 is sandwiched through (not shown). The valve plate 58 has a cylinder bore 30, that is, a suction hole 60 and a discharge hole 62 assigned to each compression chamber 33. On the other hand, a suction chamber 64, a discharge chamber 66, and an intermediate pressure chamber 68 are formed between the valve plate 58 and the cylinder head 22, and these chambers 64, 66, and 68 are independent of each other. More specifically, the intermediate pressure chamber 68 is disposed in the center of the cylinder head 22, the discharge chamber 66 has an annular shape surrounding the intermediate pressure chamber 68, and the suction chamber 64 has an annular shape surrounding the discharge chamber 66. That is, the intermediate pressure chamber 68, the discharge chamber 66, and the suction chamber 64 form a triple structure!

 [0014] The suction chamber 64 communicates with the suction hole 60 of each compression chamber 33, and is connected to the low pressure region 2 of the circulation path 2 through the suction port 4s described above. On the other hand, the discharge chamber 66

 L

 Each communicates with the discharge hole 62 of the contraction chamber 33 and is connected to the high-pressure region 2 of the circulation path 2 through the discharge port 4d described above. As is clear from Fig. 2, the suction port 4s

 H

 The discharge port 4d is formed in the cylinder head 22, respectively.

 A suction valve 70 is assigned to each of the suction holes 60 described above, and these suction valves 70 can open and close the corresponding suction ports 60. Further, a discharge valve 72 is assigned to each discharge hole 62, and these discharge valves 72 can open and close the corresponding discharge holes 62. The intake valve 70 and the discharge valve 72 are both reed valves. The suction valve 70 is disposed on one end surface of the valve plate 58 on the compression chamber 33 side, while the discharge valve 72 is disposed on the other end surface of the valve plate 58. In FIG. 2, reference numeral 73 indicates a valve retainer for restricting the opening operation of the discharge valve 72.

Furthermore, an introduction port 74 is formed in the cylinder head 22. The introduction port 74 communicates with the intermediate pressure chamber 68 described above, and is connected to the introduction path 76. As is apparent from FIG. 1, the introduction path 76 is connected to the gas-liquid separator 10 described above. In such an introduction path 76, the intermediate refrigerant in the gas phase is transferred from the gas-liquid separator 10 through the introduction port 74. It is introduced into the intermediate pressure chamber 68.

 On the other hand, a rotary valve 78 is disposed between the intermediate pressure chamber 68 and the main shaft 34, and the rotary valve 78 has a cylindrical shape and is rotatably supported with respect to the cylinder block 26. That is, a cylinder hole 79 for receiving the rotary valve 78 is formed in the cylinder block 26, and the rotary valve 78 is airtightly fitted in the cylinder hole 79.

 The rotary valve 78 is positioned coaxially with the main shaft 34 and is integrally coupled to the main shaft 34. Specifically, the main shaft 34 has a pin 80 protruding from the inner end thereof into the rotary valve 78, and the pin 80 is coupled to the rotary valve 78 via a key 82. Therefore, the rotary valve 78 rotates integrally with the main shaft 34. When the rotary valve 78 is rotated, the outer peripheral surface of the rotary valve 78 is in airtight contact with the inner peripheral surface of the cylinder hole 79. Further, the rotary valve 78 passes through the valve plate 58 in an airtight manner and protrudes into the intermediate pressure chamber 68 and is rotatably supported by the cylinder head 22 via a ring-shaped thrust bearing 84.

 A valve passage 86 is formed in the rotary valve 78, and the valve passage 86 has a valve port 86 a that opens to the outer peripheral surface of the rotary valve 78 and a communication port 86 b that communicates with the intermediate pressure chamber 68. As apparent from FIG. 2, the valve port 86a is positioned in the vicinity of one end face of the valve plate 58 described above.

 Furthermore, a plurality of connection holes 88 are formed in the cylinder block 26, and these connection holes 88 are assigned to the compression chambers 33. More specifically, each connection hole 88 is a radial hole extending from the inner peripheral surface of the cylinder hole 79 toward the corresponding compression chamber 33, and in the vicinity of one end surface of the valve plate 58, the compression chamber 33. And an inner end that opens to the inner peripheral surface of the cylinder hole 79. The outer end of each connection hole 88 is always connected to the corresponding compression chamber 33 regardless of the reciprocation of the binder 32. In contrast, the inner ends of the connection holes 88 are arranged at equal intervals in the circumferential direction of the rotary valve 78, and are intermittently connected to the valve port 86a of the valve passage 86 when the rotary valve 78 is rotated. Is done. That is, the inner end of the connection hole 88 is arranged on a rotation locus drawn by the valve port 86a while the rotary valve 78 is rotating.

Accordingly, when the rotary valve 78 is rotated together with the main shaft 34, the valve ports 86a of the valve passage 88 are sequentially connected to the connection holes 88 of the compression chambers 33. This means that during rotation of the rotary valve 78, the intermediate pressure chamber 68 is sequentially connected to each compression chamber 33 by the rotary valve 78. The rotary valve 78 sequentially opens and closes each connection hole 88, The intermediate refrigerant in the intermediate pressure chamber 68 is distributed to each compression chamber 33. It is a valve arrangement. Here, the distribution timing and distribution period of the intermediate refrigerant from the intermediate pressure chamber 68 to the compression chamber 33 will be apparent from the following description.

 As described above, when the main shaft 34 is rotated, each piston 32 reciprocates in the corresponding cylinder bore 30 sequentially. Therefore, the refrigerant in the suction chamber 64 is sucked into each compression chamber 33 through the suction valve 70 and the suction hole 60. Thereafter, the sucked refrigerant is compressed in each compression chamber 33, and the compressed refrigerant is discharged from the compression chamber 33 to the discharge chamber 66 through the discharge hole 62 and the discharge valve 72. The discharge chamber 66 is connected to the high pressure area 2 of the circulation path 2.

 H

 Therefore, the discharged refrigerant is supplied from the compressor 2 to the condenser 6. On the other hand, since the suction chamber 64 is connected to the low pressure region 2 of the circulation path 2, the cooling chamber 33 is returned to the compression chamber 33.

 L

 The medium is sucked from the suction chamber 64.

 On the other hand, the rotary valve 78 rotates integrally with the main shaft 34, and the valve port 86a of the valve passage 86 of the rotary valve 78 is distributed to the connection hole 88 of the compression chamber 33 in a state where the refrigerant is in the compression process. Connected only for timing and distribution period. That is, the rotary valve 78 is opened at the distribution timing and closed at the end of the distribution period. Here, the distribution timing and the distribution period are set within the time period until the pressure of the refrigerant in the compression process in the compression chamber 33 rises to the pressure of the intermediate refrigerant in the intermediate pressure chamber 68.

 Accordingly, when the rotary valve 78 is opened during the refrigerant compression process, the intermediate refrigerant in the intermediate pressure chamber 68 is injected into the compression chamber 33 through the rotary valve 78 and the connection 88. Here, a gas-phase intermediate refrigerant is introduced into the intermediate pressure chamber 68 through the introduction path 76 from the gas-liquid separator 10 described above. Therefore, the intermediate refrigerant in the intermediate pressure chamber 68, that is, the intermediate refrigerant injected into the compression chamber 33, has a temperature sufficiently lower than the discharge temperature of the refrigerant discharged from the compressor 4 and the compressor 4 force, etc. The pressure is lower than the discharged discharge pressure. As a result, the low-temperature intermediate refrigerant ejected into the compression chamber 33 is mixed with the high-temperature refrigerant in the compression process, so that the compressed refrigerant in the compression chamber 33 is cooled, and thereby discharged from the compressor 4. The temperature rise of the refrigerant is suppressed.

[0020] If the temperature rise of the discharged refrigerant is restricted in this way, even if carbon dioxide is used as the refrigerant, the heat load applied to the compressor 4 is greatly reduced, and for example, R1234YF or the like is used as the refrigerant. Even if a new refrigerant containing a hydrocarbon double bond is used, the double bond will not be decomposed. Therefore, the compressor 4 of the present invention is favorable for preventing global warming. It enables the use of a suitable refrigerant, i.e. carbon dioxide or the new refrigerant mentioned above.

 Further, as described above, if a low-temperature refrigerant is injected into the compression chamber 33, the compression efficiency of the refrigerant in the compression chamber 33 is increased, and the energy efficiency of the refrigerator is dramatically improved. That is, the multi-effect cycle required for this kind of refrigerator can be easily realized.

 On the other hand, the aforementioned crank chamber 24 is connected to each of the suction chamber 64 and the discharge chamber 66 via connection passages 96 and 98 indicated by a one-dot chain line in FIG. The valve plate 58 and the cylinder block 26 are passed through. A throttle 100 is disposed in the connection passage 96, while an electromagnetic control valve 102 is disposed in the connection passage 98. This electromagnetic control valve 102 controls the amount of high-pressure refrigerant that should flow from the discharge chamber 66 into the crank chamber 24 to adjust the pressure in the crank chamber 24.

The inclination angle of the swash plate 46 described above is determined by the compression reaction force applied from each piston 32 to the front surface of the swash plate 46 and the pressure in the crank chamber 24 applied to the rear surface of the swash plate 46, that is, the back pressure. Therefore, it changes as the pressure in the crank chamber 24 is adjusted. Since the inclination angle of the swash plate 46 determines the stroke of each piston 32, the refrigerant discharge amount from the compressor 4 is variable from the inclination angle of the swash plate 46.

 Since the connection hole 86 of the compression chamber 33 described above is disposed near the top dead center of the piston 32, even if the stroke of the piston 32 is changed, the distribution timing and distribution period of the rotary valve 78 with respect to each compression chamber 33 are not changed. It does not change. Therefore, the relationship between the pressure of the refrigerant discharged from the compressor 4 and the pressure of the intermediate refrigerant in the intermediate pressure chamber 68 is kept almost constant regardless of the stroke of the piston 32, and the refrigerant is compressed. The power S is used to stably inject the low-temperature intermediate refrigerant into the compression chamber 33.

 The present invention can be variously modified without being limited to the above-described embodiment.

 For example, FIG. 3 shows a rotary valve 78 that is rotated independently of the main shaft 34. In this case, the rotary valve 78 is connected to the output shaft 92 of the electric motor 90, and the electric motor 90 is attached to the outer surface of the cylinder head 22. Normally, the electric motor 90 is a force that rotates the rotary valve 78 in synchronization with the rotation of the main shaft 34. The distribution timing and the distribution period of the rotary valve 78 are adjusted as necessary.

FIG. 4 shows an electromagnetic on-off valve 94 used in place of the rotary valve 78. Each solenoid valve 94 It is allocated and arranged in the compression chamber 33 and exhibits the same function as the rotary valve 78 described above. Furthermore, the reciprocating compressor of the present invention may be a fixed capacity type or may be driven by an electric motor instead of the engine. The type of reciprocating motion is not limited to the illustrated swing plate type, but may be a swash plate type or other axial piston type! /.

Claims

The scope of the claims [1] a housing having a cylinder bore;  A piston that is fitted to form a compression chamber in the cylinder bore and is capable of reciprocating in the cylinder bore, and by reciprocation thereof, sucks refrigerant into the compression chamber and sucks into the compression chamber. A piston that performs a series of processes including compression of refrigerant and discharge of compressed refrigerant from the compression chamber, and the discharged refrigerant is supplied to a refrigerant circulation path of a refrigerator;  An introduction device that is arranged in the housing and introduces an intermediate refrigerant into the compression chamber from the refrigerant circulation path for a predetermined period when the refrigerant is in a compression process in the compression chamber. An introducing device having a pressure higher than the pressure of the compressed refrigerant in the room;  A reciprocating compressor of a refrigerator equipped with  2. The reciprocating compressor of a refrigerator according to claim 1, wherein the introduction device introduces the intermediate refrigerant having a temperature lower than a temperature of the compressed refrigerant in the compression process into the compression chamber.  [3] The introduction device includes:  An intermediate pressure chamber formed in the housing and supplied with the intermediate refrigerant from the refrigerant circulation path;  A connection passage connecting the intermediate pressure chamber and the compression chamber;  A valve provided in the connection passage for opening and closing the connection passage, in a time zone until the pressure of the compressed refrigerant in the compression chamber reaches the pressure of the intermediate refrigerant in the intermediate pressure chamber. And a valve for opening the connecting passage  The reciprocating compressor of the refrigerator according to claim 1, comprising: 4. The reciprocating compressor of the refrigerator according to claim 3, wherein the valve is a rotary valve that is mechanically coupled to the main shaft and rotates integrally with the main shaft. 5. The reciprocating compressor for a refrigerator according to claim 3, wherein the valve is a rotary valve that is rotated by a motor independent of the main shaft. 6. The reciprocating compressor of the refrigerator according to claim 3, wherein the valve is a solenoid valve. 7. The reciprocating compressor for a refrigerator according to claim 1, further comprising a variable capacity mechanism that varies a discharge amount of the compressed refrigerant, the variable capacity mechanism having a swash plate. 8. The reciprocating compressor of the refrigerator according to claim 1, wherein the refrigerant is carbon dioxide. [9] The reciprocating compressor of the refrigerator according to claim 1, wherein the refrigerant includes a compound having a hydrocarbon double bond.