JP4156114B2 - Reciprocating compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vapor compression refrigeration apparatus suitably used as an air conditioner for automobiles, business use, or home use.
[0002]
[Prior art]
In today's world where it is demanded globally to prevent global warming due to chlorofluorocarbons, in the field of vapor compression refrigeration cycles where chlorofluorocarbons have been used as refrigerants, carbon dioxide, for example, is one of the countermeasures against defluorocarbons. (CO ₂ Vapor compression refrigeration cycle (hereinafter referred to as CO) ₂ Abbreviated as cycle. ) Has been proposed.
[0003]
[Problems to be solved by the invention]
However, CO ₂ In the cycle, compared with the one using R134a or other Freon, the compression efficiency in the compressor decreases, the deterioration of the lubricating oil inside the compressor due to the increase in the refrigerant discharge temperature, the coefficient of performance of the refrigeration cycle (COP: Coefficient of Performance) ) And other problems, and improving them is an issue.
[0004]
The present invention has been proposed in view of such circumstances, and is ₂ An object of the present invention is to provide a swing swash plate type reciprocating compressor that is used in a cycle, reduces a decrease in compression efficiency, lowers a refrigerant discharge temperature, and realizes an improvement in COP at low cost.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention is such that the rotational driving force transmitted to the drive shaft by the external drive source has a swash plate attached to the drive shaft and a planar substantially disk shape, and is mainly accompanied with the rotation of the swash plate. A rocking plate that rocks with the center position of the surface as the rocking center point, and a piston rod connecting portion provided on the main surface of the rocking plate around the rocking center point (N is a plurality). The gas phase is transmitted from the outside to the N piston rods that reciprocate in the axial direction of the drive shaft as the swing plate swings, and to the N pistons connected to each piston rod. In a reciprocating compressor that sucks and compresses the refrigerant with the N pistons and circulates them in the air conditioning system, the drive shaft and the swash plate are rotatably held, and a crank chamber for storing the swing plate and each piston rod is provided. The cylinder in which the piston is housed has a drive shaft The cylinder block body includes N cylinder block bodies formed in the periphery, a cylinder head in which a refrigerant passage communicating with each cylinder is formed, and a valve mechanism disposed between the cylinder block body and the cylinder head. The N cylinders include a first compression cylinder that compresses refrigerant supplied from the outside and a second compression cylinder that further compresses the compressed refrigerant. A refrigerant suction passage for supplying refrigerant from the outside to the first compression cylinder via the valve mechanism, and a refrigerant for supplying the refrigerant compressed by the piston in the first compression cylinder to the second compression cylinder via the valve mechanism A discharge suction passage and a refrigerant discharge passage for discharging the refrigerant compressed by the piston in the second compression cylinder to the outside through the valve mechanism, and the N pistons of the swing plate The first piston rod connection for the piston rod connected to the piston in the first compression cylinder is the second connection for the piston rod connected to the piston in the second compression cylinder. It is provided at a predetermined position on the main surface having a larger swing radius than the piston rod connecting portion, and is offset to the drive shaft side by a predetermined distance.
[0006]
In the reciprocating compressor according to the present invention, the discharge side of the first compression cylinder and the suction side of the second compression cylinder are connected by the refrigerant discharge suction passage of the cylinder head, and the drive shaft and the swash plate rotate. The plurality of pistons sequentially reciprocate in the cylinder through the swing plate and each piston rod, and the refrigerant compressed by the piston in the first compression cylinder is further compressed by the piston in the second compression cylinder. . At this time, the first piston rod connecting portion is on the rocking plate main surface having a larger rocking radius than the second piston rod connecting portion for the piston rod connected to the piston in the second compression cylinder. Therefore, the piston stroke for the first compression cylinder is larger than the piston stroke for the second compression cylinder. Further, since the first piston rod connecting portion is offset to the drive shaft side by a predetermined distance, a difference in piston top clearance caused by a difference in piston stroke is eliminated.
[0007]
The total displacement of the refrigerant by the piston in the second compression cylinder is preferably 70% to 90% of the total displacement of the refrigerant by the piston in the first compression cylinder.
[0008]
Further, it is preferable that an intermediate pressure suction port for sucking in an external refrigerant as an intermediate pressure is provided in the refrigerant discharge suction passage of the cylinder head. That is, when supplying the refrigerant compressed by the piston in the first compression cylinder to the second compression cylinder via the refrigerant discharge suction passage, the refrigerant having a low temperature from the intermediate pressure suction port is combined with the second compression cylinder. Thus, the refrigerant discharge temperature after compression by the piston in the second compression cylinder can be kept low.
[0009]
Furthermore, by using a hollow piston having a hollow portion in which an inert gas is sealed under pressure, efficiency can be improved during driving due to weight reduction.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. A reciprocating compressor to which the present invention is applied is used as a compressor of a vapor compression refrigeration cycle as shown in FIG. That is, the vapor compression refrigeration cycle 1 in FIG. 1 (hereinafter simply referred to as the refrigeration cycle 1) is mounted on a vehicle such as an automobile, for example. ₂ ) As a refrigerant, a compressor 2 that compresses the refrigerant in a gas phase, and a radiator (gas cooler) 3 that cools the refrigerant compressed by the compressor 2 by exchanging heat with outside air or the like, A first expansion valve 4 that is disposed downstream of the gas cooler 3 and controls the pressure of the refrigerant from the gas cooler 3, and a refrigerant CO disposed downstream of the first expansion valve 4 ₂ The gas-liquid separator 5 that stores the gas in two phases, the gas phase and the liquid phase, the second expansion valve 6 that controls the pressure of the refrigerant flowing out of the gas-liquid separator 5, and the refrigerant from the second expansion valve 6 And an evaporator 7 which is evaporated and supplied to the compressor 2.
[0011]
In this refrigeration cycle 1, as shown in FIG. 1, a compressor 2 and a gas cooler 3 are connected to a pipe P. ₁ The gas cooler 3 and the first expansion valve 4 are connected to the pipe P. ₂ The first expansion valve 4 and the gas-liquid separator 5 are connected to the pipe P. _Three The gas-liquid separator 5 and the second expansion valve 6 are connected to the pipe P. _Four The second expansion valve 6 and the evaporator 7 are connected to the pipe P. _Five The evaporator 7 and the compressor 2 are connected to the pipe P. ₆ Furthermore, the gas-liquid separator 5 and the compressor 2 are connected to the pipe P. ₇ Are connected to each other.
[0012]
Next, the configuration of the compressor 2 used in the refrigeration cycle 1 will be described. As shown in FIG. 2, the compressor 2 is a reciprocating compressor that obtains a compression force by reciprocating movement of a plurality of pistons. In this embodiment, six pistons are provided. The compressor 2 is configured such that the rotational driving force transmitted to the drive shaft is transmitted to the six pistons via a crank mechanism such as a swash plate and a swing plate.
[0013]
As shown in FIG. 2, the compressor 2 is assembled with a front housing 11, a cylinder block 12, and a cylinder head 13 to form a compressor casing as a casing. In the compressor casing, a space formed by the front housing 11 and the cylinder block 12 is a crank chamber 20, and a swash plate 18 and a swash plate 18 integrated with the drive shaft 14 are formed in the crank chamber 20. An oscillating plate 19 that oscillates along with the rotation of the cylinder, a piston rod 21 attached to the oscillating plate 19, and the like are disposed. In the compressor casing, six cylinders 25 are formed in communication with the crank chamber 20, and a piston 15 is provided for each cylinder 25.
[0014]
In the compressor 2, a through hole portion 16 for supporting the drive shaft 14 is formed in the center of the front housing 11, and the drive shaft 14 can rotate via a bearing 17 with respect to the through hole portion 16. It is attached. Further, a swash plate 18 is connected to the drive shaft 14 and both are integrated. The swash plate 18 has a substantially circular plane, and has an upper surface (inclined surface) inclined at an angle θ with respect to the bottom surface, as shown in FIG.
[0015]
A swing plate 19 is assembled to the swash plate 18 so as to be rotatable relative to the inclined surface. The swing plate 19 is connected to each piston 15 and a universal joint (via a piston rod 21). Connected by universal joint method. The swing plate 19 is supported via a spherical bearing 24 by a support member 23 attached to the central through hole portion 22 of the cylinder block 12. The rocking plate 19 and the support member 23 are each provided with a locking portion in the vicinity of the mounting position of the bearing 24, and these locking portions prevent relative rotation between the rocking plate 19 and the support member 23. ing. As a result, when the swash plate 18 rotates, the swing plate 19 swings in the crank chamber 20 around the center point (point C in FIG. 2) of the bearing 24 located at the center of the main surface. 18 is not rotated.
[0016]
In the cylinder block 12, as shown in FIG. 3, six cylinders 25 having a circular planar shape are provided radially around the through-hole portion 22, and have the same diameter. Here, in each cylinder 25, as shown by a wavy line in FIG. 3, there are two types, one arranged near the center (through hole 22) and one arranged far from the center. Alternatingly arranged. In each cylinder 25, the first compression chamber 25A is disposed at a position far from the through-hole portion 22, and the second compression chamber 25B is disposed at a position closer thereto. That is, there are three first compression chambers 25A and two second compression chambers 25B, and the first compression chamber 25A → the second compression chamber 25B → the first compression chamber 25A →. They are arranged alternately so that they are of different types. The cylinders 25 are arranged concentrically between the first compression chambers 25A and between the second compression chambers 25B.
[0017]
Further, in the compressor 2, as shown in FIGS. 2 and 4, the position of the piston rod 21 attached to the swing plate 19 is also relative to the piston 15 in the first compression chamber 25A and in the second compression chamber 25B. It differs from that for the piston 15. In other words, as shown in FIG. 4, the swing plate 19 has six piston rod mounting portions 28 to which the piston rod 21 is mounted from the center of the main surface of the swing plate 19, and these piston rod mounting portions 28. The position (pitch radius) from the center of the main surface of the swing plate 19 is the position Ra for the piston (28A) in the first compression chamber 25A and the position Rb for the piston (28B) in the second compression chamber 25B. In contrast, Ra> Rb.
[0018]
By adopting such a configuration, in the compressor 2, the movement amount (stroke) of the piston 15 arranged in the first compression chamber 25A is larger than the stroke of the piston of the second compression chamber 25B. The total displacement of the refrigerant by the piston 15 in the first compression chamber 25A is larger than the total displacement of the refrigerant by the piston 15 in the second compression chamber 25B. Here, if the total displacement of the refrigerant by the piston 15 in the second compression chamber 25B is set in the range of 70% to 90% of the total displacement of the refrigerant by the piston 15 in the first compression chamber 25A, the compression efficiency is good. It has been confirmed by the present inventors.
[0019]
If Ra> Rb, the position of the piston 15 at the top dead center (piston top clearance) is different between the first compression chamber 25A and the second compression chamber 25B, and some adjustment is required. As means for performing this adjustment, the length L of the piston rod 21 shown in FIG. ₁ Or the length L from the upper surface of the piston 15 to the mounting position of the piston rod 21 ₂ Can be changed between the first compression chamber 25A and the second compression chamber 25B. However, when such a means is adopted, the piston rod 21 or the piston 15 becomes two types, and the parts cannot be shared.
[0020]
Therefore, in this embodiment, as shown in FIG. 2, the depth positions from the upper surface of the swing plate 19 provided with the piston rod mounting portion 2828A and the piston rod mounting portion 28B are made different from each other. Specifically, when an imaginary line parallel to the lower surface of the swing plate 19 (or the upper surface of the swash plate 18) is drawn from the center position C of the bearing 24, which is the center of rotation (swing) of the swing plate 19 In addition, the center point of the piston rod mounting portion 28B corresponding to the second compression chamber 25B, that is, the point B serving as the rotation center position of the piston rod 21 is on this imaginary line, while the piston rod mounting portion corresponding to the first compression chamber 25A. The positional relationship is such that point A, which is the center position of 28BA, is offset from the imaginary line by a distance X toward the drive shaft 14 side, that is, the side away from the cylinder 25A.
[0021]
By using such an adjusting means, in the compressor 2, the first compression chamber 25A and the second compression chamber 25B use the same piston 15 and piston rod 21 as each other, and the first compression chamber 25A The piston stroke can be secured relatively large, and the piston top clearance can be made the same between the first compression chamber 25A and the second compression chamber 25B. That is, in this compressor 2, both the piston 15 and the piston rod 21 can be configured by the same parts in the first compression chamber 25A and the second compression chamber 25B, and cost reduction is realized.
[0022]
Note that the value of the offset distance X is determined by the values of Ra, Rb, and θ.
X≈ (Ra−Rb) tan θ
It will be represented by
[0023]
As shown in FIG. 2, each piston 15 has a hollow structure in which a cavity 30 is formed for weight reduction, and an inert gas is sealed in the cavity 30 under pressure. Here, for example, nitrogen gas is used as the inert gas. Further, the pressurizing pressure value of the inert gas in the cavity 30 is set to an intermediate value of the pressure applied to each piston during the operation of the compressor 2. In this compressor 2, 30 kg / cm at low pressure with respect to each piston during operation. ² 110kg / cm at high pressure ² In this case, the inert gas is 50-60 kg / cm. ² Good durability performance was obtained when sealed in the cavity 30 with a pressurized pressure of.
[0024]
As shown in FIG. 3, valve receiving portions (recesses) 26 (26A, 26B) for limiting the amount of movement of a suction valve, which will be described later, are formed at the upper ends of the cylinders 25, respectively. Here, the recess 26 </ b> A of the first compression chamber 25 </ b> A is provided at a position toward the inside (through hole 22 side) of the cylinder block 12, and the recess 26 </ b> B of the second compression chamber 25 </ b> B is at a position toward the outside of the cylinder block 12. Is provided. In the cylinder block 12, a screw hole 27 for attaching a first discharge valve 45 described later is formed in the vicinity of the first compression chamber 25A.
[0025]
As shown in FIGS. 2 and 5, the valve plate 31 has a disk-like outer shape, and a suction valve member 41, a second discharge valve 44, and a second discharge valve, which will be described later, are disposed at the center position of the main surface. A central hole 32 for screwing the receiving member 46 with a bolt 47 and a nut 48 is provided. In addition, suction holes 33 and 34 and discharge holes 35 and 36 are formed on the main surface of the valve plate 31. Here, the suction hole 33 is a first suction hole for supplying refrigerant to the first compression chamber 25A, and the suction hole 34 is a second suction hole for supplying refrigerant to the second compression chamber 25B. On the other hand, the discharge hole 35 is a first discharge hole for discharging the refrigerant compressed in the first compression chamber 25A, and the discharge hole 36 is a second discharge hole for discharging the refrigerant compressed in the second compression chamber 25B. It is.
[0026]
Grooves 37, 38, and 39 for attaching the intake and discharge valves are formed on both main surfaces of the valve plate 31. 5 is a view showing the valve plate 31 from the lower side (left side in FIG. 2), and the groove portions 38 and 39 shown by dotted lines are provided on the main surface on the opposite side. Each of the groove portions 37 to 39 has substantially the same planar shape as each valve, and has such a depth that each valve is flush with both main surfaces of the valve plate when the valves are aligned and fitted. Is formed.
[0027]
In the compressor 2, the intake and discharge valves are attached to both main surfaces of the valve plate 31, so that the valves are arranged in a positional relationship as shown in FIG. 6. That is, the valve plate 31 is provided with the first discharge valve 45 for the first compression chamber 25A and the second discharge valve 44 for the second compression chamber 25B on the main surface facing the cylinder head 13. A plate-like suction valve member in which three first suction valves 42 for the first compression chamber 25A and three second suction valves for the second compression chamber 25B are respectively formed on the main surface on the opposite side of the valve plate 31. 41 is attached. 6 is a diagram showing the positional relationship of each valve from the upper side (right side of FIG. 2). For convenience of explanation, the illustration of the valve plate 31 is omitted and only the position of the hole is extracted and shown. Yes.
[0028]
Here, the intake valve member 41 branches in six directions from the center, and the main surface of a large piece extending in three directions is cut out to form the first intake valve 42. The distal end portion of the first intake valve 42 is positioned on the valve receiving portion 26 </ b> A of the cylinder 25 by attaching the intake valve member 41 to the groove portion 37 of the valve plate 31. A discharge hole 41 b is formed at a position corresponding to the first discharge hole 35 of the valve plate 31 on the proximal end side of the first suction valve 42. On the other hand, a small piece extending in three directions of the suction valve member 41 is a second suction valve 43, and a discharge hole is formed at a position corresponding to the second discharge hole 36 of the valve plate 31 on the proximal end side of this valve. A portion 41a is formed.
[0029]
The first discharge valve 45 for the first compression chamber 25A has a substantially planar “I” shape, and a hole 45a to which a screw is attached is formed on the base end side. The first discharge valve 45 is attached to the groove 39 of the valve plate 31 with a screw, so that the tip side closes the first discharge hole 35 of the intake valve 31.
[0030]
As shown in FIG. 6, the second discharge valve 44 of the second compression chamber is formed with a hole 44a for screwing in the center, and branches from the center in a direction of 120 degrees with each other. Two discharge valves are formed. The three discharge valves of the second discharge valve 44 close each of the second discharge holes 36 because the tip side is located on the second discharge hole 36 of the valve plate 31. A second discharge valve receiving member 46 shown in FIG. 2 having substantially the same planar shape as the second discharge valve 44 is attached to the second discharge valve 44.
[0031]
FIG. 7 is a plan view showing the cylinder head from the inner side. As shown in FIGS. 2 and 7, the cylinder head 13 has a side wall 51 formed from the side edge, and a rising wall 52 is substantially the same as the side wall 51 from the main surface surrounded by the side wall 51. It is formed at a height of In the cylinder head 13, a space surrounded by the side wall portion 51 and the rising wall portion 52 is an intermediate pressure suction chamber 53, and an intermediate portion that is a hole portion for supplying intermediate pressure from the outside to this space. A pressure suction port 54 communicates with the main surface. The intermediate pressure suction chamber 53 is a space that allows the discharge side of the first compression chamber 25A and the suction side of the second compression chamber 25B to communicate with each other, and the intermediate pressure supplied from the outside through the intermediate pressure suction port 54. Is a space for guiding to the second compression chamber. In this embodiment, the pipe P is connected to the intermediate pressure inlet 54. ₇ As shown in FIG. 1, the intermediate pressure from the gas-liquid separator 5 is taken in.
[0032]
In the cylinder head 13, the rising wall portion 52 forms a second discharge chamber 55 into which the refrigerant from the second compression chamber 25 </ b> B is discharged in the center. The second discharge chamber 55 is continuous with a discharge port 56 provided in the center of the main surface of the cylinder head 13. Further, three first suction chambers 57 for the first compression chamber 25 </ b> A are formed by the rising wall portion 52 outside the second discharge chamber 55. Each of the first suction chambers 57 is continuous with a suction hole 58 provided in the main surface of the cylinder head 13. Further, the first suction chambers 57 communicate with each other through a communication hole 59 (see FIG. 2) having a square cross section indicated by a dotted line in FIG. In addition, the positional relationship at the time of the assembly | attachment of each member mentioned above is shown in FIG.
[0033]
In the operation of the compressor 2, the pipe P from the outlet of the evaporator 7 in FIG. ₆ Is connected to the suction hole 58 of the compressor 2 and the pipe P to the inlet of the gas cooler 3 ₁ Is connected to the discharge port 56 from the second compression chamber. Further, as described above, the pipe P to which the intermediate pressure from the gas-liquid separator 5 is supplied ₇ Is connected to the intermediate pressure inlet 54.
[0034]
When the drive shaft 14 is rotated by the driving force of the engine or motor, the refrigerant CO ₂ Flows into the first suction chamber 57, and the piston 15 in the first compression chamber 25A performs suction and first-stage compression in order from the one moving to the bottom dead center side. Refrigerant CO with first stage compression ₂ The first discharge valve 45 is lifted to flow into the intermediate pressure suction chamber 53 from the first discharge hole 35, and subsequently sucked in order from the piston 15 in the second compression chamber 25B moving to the bottom dead center side. And second-stage compression is performed. Refrigerant CO with second stage compression ₂ Lifts the second discharge valve 44 from the second discharge hole 36 to the discharge chamber 56 and the pipe P. ₁ After that, it is supplied to the gas cooler 3.
[0035]
In this compressor 2, the refrigerant CO that has been compressed in the first stage during the suction by the piston 15 in the second compression chamber 25B. ₂ And low-temperature refrigerant CO from the gas-liquid separator 5 ₂ Is sucked in, the refrigerant discharge temperature after compression by the piston 15 in the second compression chamber 25B is kept low, and deterioration of the lubricating oil inside the compressor is prevented.
[0036]
Thus, in the compressor 2, the refrigerant CO ₂ Is compressed in two times, and the compression ratio in one compression can be reduced to improve the compression efficiency. Further, in the refrigeration cycle 1 using the compressor 2, the characteristics as shown in the ph diagram of FIG. 9 are obtained, and it is possible to improve COP while suppressing the discharge temperature of the refrigerant. In FIG. 9, the pressure Ps indicates the pressure in the evaporator 7, the pressure Pd indicates the pressure in the gas cooler 3, the pressure Pm indicates the pressure from the gas-liquid separator 5, and the point P ₁ ~ P ₇ Is the piping P shown in FIG. ₁ ~ P ₇ The state is shown. In addition, Aout indicates a state when discharging from the first compression chamber 25A of the compressor 2, and Bin indicates a state when sucking into the second compression chamber 25B.
[0037]
Further, in the compressor 2, since the cavity 15 is provided in the piston 15 and the inert gas is pressurized and sealed in the cavity 30, both weight reduction and pressure resistance can be achieved, and the efficiency during driving can be improved. Figured. Furthermore, since the piston 15 and the piston rod 21 used in the first compression chamber 25A and the second compression chamber 25B are made common, it is possible to provide a low-cost two-stage compression compressor. Become.
[0038]
In the above-described embodiment, an example in which the present invention is applied to a compressor having six pistons is shown, but the number of pistons is not limited to this.
[0039]
【The invention's effect】
As described above in detail, according to the reciprocating compressor of the present invention, the refrigerant compressed by the piston in the first compression cylinder is further compressed by the piston in the second compression cylinder via the refrigerant discharge suction passage. Then, since the refrigerant is compressed in two steps, the compression ratio in one compression can be reduced to reduce the reduction in compression efficiency. Further, the first piston rod connecting portion is on the rocking plate main surface having a larger rocking radius than the second piston rod connecting portion for the piston rod connected to the piston in the second compression cylinder. Since it is at a predetermined position and is offset toward the drive shaft by a predetermined distance, the piston stroke for the first compression cylinder is made larger than the piston stroke for the second compression cylinder while eliminating the difference in piston top clearance. Therefore, it is possible to appropriately adjust the total displacement of the refrigerant by each piston, and further to reduce the cost by using common parts for the piston and the piston rod.
[0040]
An intermediate pressure suction port is provided in the refrigerant discharge suction passage, and when the refrigerant compressed by the piston in the first compression cylinder is supplied to the second compression cylinder through the refrigerant discharge suction passage, the intermediate pressure suction port is provided. By sending the low-temperature refrigerant together into the second compression cylinder, the compressed refrigerant is cooled and then compressed again, so that the refrigerant discharge temperature after compression by the piston in the second compression cylinder is kept low, An increase in power accompanying a decrease in compression efficiency due to an increase in compression ratio can be avoided. Moreover, deterioration of the lubricating oil inside the compressor can be prevented. Furthermore, by using a hollow piston having a hollow portion in which an inert gas is pressurized and sealed, both weight reduction and pressure resistance can be achieved, and efficiency during driving can be improved.
[0041]
Therefore, according to the present invention, it is possible to provide, at a low cost, a swing swash plate type compressor that reduces the decrease in compression efficiency, lowers the refrigerant discharge temperature, and realizes an improvement in COP.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a refrigeration cycle.
FIG. 2 is a cross-sectional view for explaining a configuration of a compressor.
FIG. 3 is a plan view of a cylinder block for explaining the configuration and arrangement of each cylinder.
FIG. 4 is a plan view of a swing plate for explaining a position of a piston rod mounting portion.
FIG. 5 is a plan view showing a configuration of a valve plate.
FIG. 6 is a plan view for explaining the configuration and arrangement of an intake valve and a discharge valve.
FIG. 7 is a plan view showing a configuration of a cylinder head.
FIG. 8 is a perspective view showing a positional relationship between members such as a valve plate and a cylinder head.
FIG. 9 is a ph diagram in the refrigeration cycle.
[Explanation of symbols]
1 Refrigeration cycle
2 Compressor
3 Gas cooler
4 First expansion valve
5 Gas-liquid separator
6 Second expansion valve
7 Evaporator
P ₁ ~ P ₇ Piping
11 Front housing
12 Cylinder block
13 Cylinder head
14 Drive shaft
15 piston
18 Swashplate
19 Swing plate
20 Crank chamber
21 Piston rod
24 Bearing
25 cylinders
25A 1st compression chamber
25B Second compression chamber
26 (26A, 26B) Recess
27 Screw holes
28 (28A, 28B) Piston rod mounting part
30 cavity
31 Valve plate
41 Suction valve member
42 First intake valve
43 Second intake valve
44 Second discharge valve
45 First discharge valve
51 Side wall
52 Rising wall
53 Intermediate pressure suction chamber
54 Intermediate pressure inlet
55 Second discharge chamber
56 Discharge port
57 First suction chamber
58 Suction hole
59 Communication hole

Claims (5)

The rotational driving force transmitted to the drive shaft by the external drive source is a swash plate attached to the drive shaft and has a substantially flat disk shape, and swings with the center position of the main surface as the swing center point as the swash plate rotates. Connected to the piston rod connecting portion provided on the main surface of the swing plate and around the swing center point (N is a plurality), and is driven as the swing plate swings. Gas phase refrigerant that is transmitted to N piston rods that reciprocate in the axial direction of the shaft and N pistons connected to each piston rod and is supplied from the outside is sucked by the N pistons, In reciprocating compressors that compress and circulate to the air conditioning system,
The drive shaft and the swash plate are rotatably held, have a crank chamber for storing the swing plate and the piston rods, and N cylinders are formed around the drive shaft. A cylinder block body, a cylinder head formed with a refrigerant passage communicating with each cylinder, and a valve mechanism disposed between the cylinder block body and the cylinder head,
The cylinder block main body includes a first compression cylinder in which the N cylinders compress refrigerant supplied from the outside and a second compression cylinder that further compresses the compressed refrigerant.
The refrigerant passage of the cylinder head includes a refrigerant suction passage for supplying an external refrigerant to the first compression cylinder via the valve mechanism, and a refrigerant compressed by a piston in the first compression cylinder. A refrigerant discharge suction passage for supplying the refrigerant to the second compression cylinder via the mechanism, and a refrigerant discharge passage for discharging the refrigerant compressed by the piston in the second compression cylinder to the outside via the valve mechanism,
The N piston rod connecting portions of the swing plate are connected to the piston in the second compression cylinder by the first piston rod connecting portion for the piston rod connected to the piston in the first compression cylinder. The piston rod to be connected is provided at a predetermined position on the main surface having a larger swing radius than the second piston rod connecting portion, and is offset to the drive shaft side by a predetermined distance. Reciprocating compressor. The total displacement of the refrigerant by the piston in the second compression cylinder is 70% to 90% of the total displacement of the refrigerant by the piston in the first compression cylinder. Reciprocating compressor. 2. The reciprocating compressor according to claim 1, wherein an intermediate pressure suction port for sucking an external refrigerant as an intermediate pressure is provided in the refrigerant discharge suction passage of the cylinder head. The reciprocating compressor according to claim 1, wherein the piston is a hollow piston having a hollow portion in which an inert gas is pressurized and sealed. The reciprocating compressor according to claim 1, wherein carbon dioxide (CO ₂ ) is used as the refrigerant.

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