JP2004245084A - Variable displacement compressor and refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement compressor and a refrigerating cycle capable of more strictly controlling the differential pressure between crank chamber pressure and intake chamber pressure. <P>SOLUTION: The crank chamber 5 is provided with an intake port 53 for leading in a refrigerant of low temperature and low pressure from an evaporator 400, and an intake passage 32 for communicating the crank chamber 5 with the intake chamber 7, to form a structure of leading the refrigerant of low temperature and low pressure from the evaporator 400 into the intake chamber 7 through the crank chamber 5, and the intake passage 32 is provided with a pressure control valve 33 for regulating the differential pressure between upstream crank chamber pressure Pc and downstream intake chamber pressure Ps. Since the differential pressure between the crank chamber pressure Pc and intake chamber pressure Ps can be directly controlled by the pressure control valve 33, more strict differential pressure control can be performed in comparison with the conventional constitution. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigeration cycle such as a vehicle air conditioner. Further, the present invention is a compressor that is interposed in a refrigeration cycle such as a vehicle air conditioner and adiabatically compresses refrigerant vaporized in the refrigeration cycle, wherein a crank chamber pressure on the rear side of the piston and a pressure of the piston The present invention relates to a variable displacement compressor that controls a piston stroke by adjusting a pressure difference from the suction chamber pressure on the front side to control a discharge displacement.
[0002]
[Prior art]
In the compressor, a front housing is joined to a front end face of a cylinder block having a cylinder bore to form a crank chamber, and a rear housing is joined to a rear end face of the cylinder block via a valve plate to form a suction chamber. A discharge chamber is formed, and the rotation of a drive shaft pivotally supported in the crank chamber is converted by a swash plate into a reciprocating motion of a piston in the cylinder bore, whereby refrigerant in the suction chamber is sucked into the cylinder bore and compressed, and the discharge chamber is compressed. Some discharge to the
[0003]
The discharge capacity is controlled by adjusting the pressure difference between the crank chamber pressure on the rear side of the piston and the suction chamber pressure on the front side of the piston, thereby controlling the piston stroke and controlling the discharge capacity. ing.
[0004]
In the conventional structure, by providing a bleed passage that constantly communicates the crank chamber and the suction chamber, and an air supply passage that communicates the crank chamber and the discharge chamber, and by providing a pressure control valve in the middle of the air supply passage, The crank chamber pressure is controlled by controlling the amount of refrigerant supplied to the crank chamber (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2003-13863
[Patent Document 2]
US Pat. No. 3,712,759 [0007]
[Problems to be solved by the invention]
However, in such a conventional technique, since the refrigerant in the discharge chamber having a large pressure fluctuation is supplied to the crank chamber to control the pressure in the crank chamber, it is difficult to control the pressure more strictly.
[0008]
The present invention has been made based on such prior art, and provides a variable displacement compressor capable of more strictly controlling the differential pressure between the crank chamber pressure and the suction chamber pressure, and a refrigeration cycle using the same. With the goal.
[0009]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a compressor for sucking / compressing refrigerant in a suction chamber into a cylinder bore and discharging the refrigerant into a discharge chamber by reciprocating a piston in a cylinder bore. A variable displacement compressor that controls a piston stroke by adjusting a pressure difference between the suction chamber pressure on the front side of the compressor and the suction chamber pressure,
By providing a suction port for introducing a low-temperature and low-pressure refrigerant from the evaporator to the crank chamber and providing a suction passage communicating the crank chamber and the suction chamber, the low-temperature and low-pressure refrigerant from the evaporator is supplied to the crank chamber. And a pressure control valve for adjusting a pressure difference between the crank chamber pressure on the upstream side and the suction chamber pressure on the downstream side in the suction passage. .
[0010]
According to the second aspect of the present invention, a compressor for compressing a refrigerant, a radiator for radiating heat of the high-temperature and high-pressure refrigerant compressed by the compressor, and a pressure of the low-temperature and high-pressure refrigerant cooled by the radiator are controlled. An expansion valve, and an evaporator that cools the ventilation air by an endothermic effect of the refrigerant, the pressure of which is controlled by the expansion valve,
The compressor draws and compresses the refrigerant in the suction chamber into the cylinder bore and discharges it to the discharge chamber by reciprocating a piston in a cylinder bore, and the crank chamber pressure on the rear side of the piston and the front side on the front side of the piston. A variable displacement compressor that controls a piston stroke by adjusting a differential pressure with a suction chamber pressure,
By providing a suction port for introducing a low-temperature and low-pressure refrigerant from the evaporator to the crank chamber and providing a suction passage communicating the crank chamber and the suction chamber, the low-temperature and low-pressure refrigerant from the evaporator is supplied to the crank chamber. And a pressure control valve for adjusting a pressure difference between the crank chamber pressure on the upstream side and the suction chamber pressure on the downstream side in the suction passage. .
[0011]
【The invention's effect】
According to the variable displacement compressor of the first aspect of the present invention, by providing a suction port for introducing low-temperature and low-pressure refrigerant from the evaporator to the crank chamber and providing a suction passage for communicating the crank chamber and the suction chamber, A low-temperature and low-pressure refrigerant from the evaporator is introduced into the suction chamber via the crank chamber, and a pressure control valve that adjusts a differential pressure between the upstream crank chamber pressure and the downstream suction chamber pressure in the suction passage. The pressure difference between the crank chamber pressure and the suction chamber pressure can be directly controlled by the pressure control valve interposed between the crank chamber and the suction chamber. Therefore, more strict differential pressure control is possible.
[0012]
Further, as an incidental effect, the pressure control valve provided between the crank chamber and the suction chamber is arranged in series with the expansion valve interposed in the refrigeration cycle. By disposing the expansion valves in parallel, unlike the conventional structure in which the valves interfere with each other and hunting may occur, it is possible to prevent the valves from interfering with each other.
[0013]
According to the refrigeration cycle of the second aspect of the present invention, the evaporator is provided by providing a suction passage communicating the crank chamber and the suction chamber and providing a suction port for introducing low-temperature and low-pressure refrigerant from the evaporator in the crank chamber. And a pressure control valve for adjusting the differential pressure between the upstream crank chamber pressure and the downstream suction chamber pressure is provided in the suction passage. The differential pressure between the crank chamber pressure and the suction chamber pressure can be directly controlled by a pressure control valve interposed between the crank chamber and the suction chamber. Therefore, more strict differential pressure control is possible.
[0014]
Further, as an incidental effect, the pressure control valve provided between the crank chamber and the suction chamber is arranged in series with the expansion valve interposed in the refrigeration cycle. By disposing the expansion valves in parallel, unlike the conventional structure in which the valves interfere with each other and hunting may occur, it is possible to prevent the valves from interfering with each other.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a refrigeration cycle according to an embodiment of the present invention and a variable displacement compressor interposed therein will be described with reference to the drawings. FIG. 1 is an overall schematic diagram showing a refrigeration cycle of the present embodiment, and FIG. 2 is an overall cross-sectional view of a variable displacement compressor interposed in the refrigeration cycle.
[0016]
First, the basic configuration of the refrigeration cycle will be described. The refrigeration cycle shown in FIG. 1 is used as a cooling cycle for an air conditioner for a vehicle, and uses a supercritical fluid (carbon dioxide in this example) as a refrigerant.
[0017]
The refrigeration cycle includes a compressor 1 that is connected to and driven by an engine (not shown) via an electromagnetic clutch as necessary, a radiator 100 that is connected to an outlet side of the compressor 1 via a pipe P1, The high pressure side flow path 210 of the internal heat exchanger 200 connected to the outlet side of the radiator 100 via the pipe P2, and the high pressure side flow path 210 of the internal heat exchanger 200 is connected via the pipe P3. An expansion valve 300, an evaporator 400 connected to the outlet side of the expansion valve 300 via a pipe P4, an accumulator 500 connected to an outlet side of the evaporator 400 via a pipe P5, and an accumulator 500 of the accumulator 500. A low pressure side flow path 220 of the internal heat exchanger 200 connected to the outlet side via a pipe P6, and a connection connecting the low pressure side flow path 220 of the internal heat exchanger 200 and the suction port 53 of the compressor 1. Is provided with a P7, the.
[0018]
The piping structure of the refrigeration cycle is divided into a high-pressure path formed from the discharge port 54 of the compressor 1 to the expansion valve 300 and a low-pressure path formed from the expansion valve 300 to the suction port 53 of the compressor. Is done.
[0019]
With the above configuration, the refrigerant of the refrigeration cycle circulates as follows. First, the refrigerant (carbon dioxide) compressed to the supercritical region in the compressor 1 is cooled in the radiator 100 and further flows through the low-pressure side channel 220 when flowing through the high-pressure side channel 210 of the internal heat exchanger 200. It is further cooled by exchanging heat with the flowing refrigerant. Then, the air expands when passing through the expansion valve 300 whose opening is controlled by control means (not shown), the pressure drops to the gas-liquid mixing region, and the air passing through the air passage of the air conditioner in the evaporator 400. The liquid phase component is removed by absorbing the heat of the liquid and evaporating and passing through the accumulator 500. The refrigerant that has flowed out of the accumulator 500 is superheated by exchanging heat with the refrigerant flowing through the high-pressure side channel 210 when passing through the low-pressure side channel 220 of the internal heat exchanger 200, and is returned to the compressor 1 again. Inhaled. In this way, the refrigerant circulates in the order of compressor 1 → radiator 100 → internal heat exchanger 200 → expansion valve 300 → evaporator 400 → accumulator 500 → internal heat exchanger 200 → compressor 1. Heat is absorbed by evaporator 400. A refrigeration cycle in which the radiator 200 radiates the generated heat is configured.
[0020]
This embodiment is characterized by the compressor 1 interposed in the refrigeration cycle, and will be described in detail below.
[0021]
As shown in FIG. 2, the compressor 1 of this embodiment is a swash plate type variable displacement compressor. The variable displacement compressor 1 includes a cylinder block 2 having a plurality of cylinder bores 3 arranged at equal intervals in a circumferential direction, and a crank chamber 5 which is joined to the cylinder block 2 at a front end face of the cylinder block 2. And a rear housing 6 joined to the rear end surface of the cylinder block 2 via a valve plate 9 to form a suction chamber 7 and a discharge chamber 8. The cylinder block 2, the front housing 4, and the rear housing 6 are fastened and fixed by a plurality of through bolts B.
[0022]
The valve plate 9 includes a suction hole 11 that connects the cylinder bore 3 and the suction chamber 7, and a discharge hole 12 that connects the cylinder bore 3 and the discharge chamber 8.
[0023]
On the cylinder block 2 side of the valve plate 9, a valve mechanism (not shown) for opening and closing the suction hole 11 is provided, while on the rear housing 6 side of the valve plate 9, a valve mechanism (not shown) for opening and closing the discharge hole 12. Is provided. A gasket is interposed between the valve plate 9 and the rear housing 6 to maintain the airtightness between the suction chamber 7 and the discharge chamber 8. Further, an O-ring is interposed on the peripheral edge of the valve plate 9 at the joint surface between the rear housing 6 and the cylinder block 2 to prevent the refrigerant from leaking out of the compressor 1.
[0024]
A drive shaft S is supported by bearings 17 and 18 in support holes 19 and 20 at the center of the cylinder block 2 and the front housing 4, and the drive shaft S is rotatable in the crank chamber 5.
[0025]
In the crank chamber 5, a drive plate 21 fixed to the drive shaft S, a journal 24 swingably connected to a sleeve 22 slidably fitted to the drive shaft S by a pin 23, and the journal 24 And a swash plate 26 fixed to the boss 25 of the swash plate. That is, the swash plate 26 rotates integrally with the journal 24 when the journal 24 rotates by rotating the drive shaft S.
[0026]
The inclination angle of the swash plate 26 decreases as the sleeve 22 moves closer to the cylinder block 2, while the inclination angle of the swash plate 26 decreases when the sleeve 22 moves away from the cylinder block 2. Increase. Here, when the sleeve 22 approaches the cylinder block 2 side, one of the return springs 52 is contracted, so that the elastic restoring force of the return spring 52 makes it easy for the sleeve 22 to return toward the neutral position. On the other hand, when the sleeve 22 is separated from the cylinder block 2, the other return spring 51 is contracted, so that the elastic restoring force of the return spring 51 makes the sleeve 22 easily return to the neutral position. I have. The drive plate 21 and the journal 24 have their hinge arms 21h and 24h connected via an arc-shaped long hole 27 and a pin 28, so that the maximum inclination angle and the minimum inclination angle of the swash plate 26 can be adjusted. Regulated.
[0027]
The piston 29 accommodated in each cylinder bore 3 is connected to the swash plate 26 via the piston shoes 30, 30 and reciprocates by the swing of the swash plate 26. The basic function of the compressor 1 is to compress the refrigerant sucked into the suction chamber 7 → the suction hole 11 of the valve plate 9 → the cylinder bore 3 by the piston motion of the piston 29, and the cylinder bore 3 → the discharge hole 12 of the valve plate 9 → It discharges to the discharge chamber 8.
[0028]
In order to make this discharge capacity variable, a pressure control mechanism for controlling the pressures of the crank chamber 5 and the suction chamber 7 (crank chamber pressure Pc, suction chamber pressure Ps) is provided. When the inclination angle of the swash plate 26 changes due to the pressure difference (pressure balance) between the pressure Pc and the suction chamber pressure Ps on the front side of the piston 29, the piston stroke changes, and the discharge capacity of the compressor 1 changes. ing.
[0029]
Hereinafter, this pressure control mechanism will be specifically described.
[0030]
First, the compressor 1 of this embodiment is provided with a suction port 53 for introducing a low-temperature and low-pressure refrigerant from the evaporator 400 into the crank chamber 5. A suction passage 32 is formed through the cylinder block 2, the valve plate 9, and the rear housing 6 and communicates the crank chamber 5 and the suction chamber 7. Thus, the low-temperature and low-pressure refrigerant from the evaporator 400 is introduced into the suction chamber 7 via the crank chamber 5. The suction passage 32 has substantially the same cross-sectional area as the pipes P4 to P7 of the low-pressure path of the refrigeration cycle, and has an upstream crank chamber pressure Pc and a downstream suction chamber pressure Ps in the middle of the passage 32. Is provided with a pressure control valve 33 for adjusting the differential pressure between the pressure control valve and the pressure control valve.
[0031]
That is, in this embodiment, the pressure control mechanism for controlling the pressure difference between the crank chamber pressure Pc and the suction chamber pressure Ps is constituted by the suction passage 32 and the pressure control valve 33 arranged in the suction passage 32.
[0032]
Therefore, when the crank chamber pressure Pc and the suction chamber pressure Ps are balanced by fully opening the valve body of the pressure control valve 33, the inclination angle of the swash plate 26 is maximized by the moment force acting on the swash plate 26, and the compression stroke is maximized. It becomes. On the other hand, when the valve body of the pressure control valve 33 is slightly closed and the crank chamber pressure Pc is higher than the suction chamber pressure Ps, the inclination angle of the swash plate 26 is reduced, and the compression stroke is reduced. When the differential pressure between the crank chamber pressure Pc and the suction chamber pressure Ps further increases, the inclination angle of the swash plate 26 becomes minimum (in this example, the inclination angle is 1 ° to 3 °).
[0033]
Here, the pressure control valve 33 of this embodiment is an electromagnetic pressure control valve, and a valve element (not shown) for opening and closing the suction passage 32 and a magnetic element (not shown) for generating magnetic force for opening and closing the valve element. A solenoid coil, and generates a magnetic force in the solenoid coil by a signal of an auto amplifier AMP generated based on the suction chamber pressure, the discharge chamber pressure, the outside temperature of the vehicle compartment, the temperature of the vehicle compartment, the amount of solar radiation, etc. The opening of the valve body is adjusted.
[0034]
In this embodiment, the pressure control valve 33 is configured such that the valve is fully opened when no power is supplied and fully closed when maximum power is supplied. Further, the auto amplifier AMP generates a signal for adjusting the opening degree of the valve body based on the outlet air temperature of the evaporator 400.
[0035]
Note that, for example, when the opening degree of the pressure control valve 33 is adjusted in accordance with the heat load of the refrigeration cycle by detecting the suction chamber pressure, the following is performed.
[0036]
When the heat load in the refrigeration cycle is small, the auto amplifier AMP determines that the cooling capacity may be small, and controls the current value or the duty ratio flowing through the solenoid coil so that the valve body moves in the valve closing direction. . As a result, the pressure difference between the crank chamber 5 and the suction chamber 7 increases, the inclination angle of the swash plate 26 centered on the pin 23 decreases, the compression stroke decreases, and the amount of discharged refrigerant decreases. As a result, the amount of the refrigerant circulating in the refrigeration cycle is reduced, and the amount of the refrigerant is appropriate for a low heat load.
[0037]
On the other hand, when the heat load of the refrigeration cycle is large, the auto amplifier AMP determines that the required cooling capacity is large, and changes the current value or duty ratio flowing through the solenoid coil so that the valve element moves in the valve opening direction. Control. As a result, the pressure difference between the crank chamber 5 and the suction chamber 7 decreases, the inclination angle of the swash plate 26 centering on the pin 23 increases, the compression stroke increases, and the amount of refrigerant discharged increases. As a result, the amount of the refrigerant circulating in the refrigeration cycle increases, and the amount of the refrigerant becomes appropriate according to the high heat load.
[0038]
According to the present embodiment, the following effects can be obtained by the configuration described above.
[0039]
First, by providing a suction port 53 for introducing a low-temperature and low-pressure refrigerant from the evaporator 400 into the crank chamber 5 and providing a suction passage 32 for communicating the crank chamber 5 and the suction chamber 7, the evaporator 400 is provided. Pressure is introduced into the suction chamber 7 through the crank chamber 5 through the crank chamber 5, and a pressure control for adjusting the differential pressure between the upstream crank chamber pressure Pc and the downstream suction chamber pressure Ps in the suction passage 32. Since the valve 33 is provided, the differential pressure between the crank chamber pressure Pc and the suction chamber pressure Ps can be directly controlled by the pressure control valve 33. Therefore, stricter differential pressure control can be performed as compared with the related art. In particular, as compared with the conventional structure, the differential pressure between the crank chamber 5 and the suction chamber 7 is controlled by introducing and controlling the refrigerant having a high pressure (discharge chamber pressure Pd) having a large pressure fluctuation into the crank chamber 5. Since the differential pressure can be controlled by the low-pressure refrigerant from the evaporator 400 with small pressure fluctuation, more strict differential pressure control is possible. As a result, more precise discharge capacity control becomes possible.
[0040]
Secondly, as an attendant effect of the above configuration, the pressure control valve 33 is arranged in series with the expansion valve 300 interposed in the refrigeration cycle, so that the pressure control valve is arranged in parallel with the expansion valve 300 of the refrigeration cycle. Hunting due to mutual interference between valves can be avoided as compared with the conventional structure. As a result, the refrigeration cycle is stabilized.
[0041]
Third, as an inconsequential effect of the above configuration, the sliding components (S, 21 to 30, 35, 51, 52, etc.) in the crank chamber 5 are introduced to introduce the low-temperature suction refrigerant from the evaporator 400 into the crank chamber 5. ) Can be efficiently cooled, and the durability of the sliding parts is improved.
[0042]
Fourth, as an ancillary effect of the above configuration, the lubricating oil conveyed together with the low-temperature suction refrigerant from the evaporator 400 is introduced into the crank chamber 5, so that the high-temperature high-temperature entrained by blow-by gas As compared with the case of supplying low-viscosity lubricating oil to the sliding parts in the crank chamber 5, the lubricating oil can be supplied to the sliding parts in the compressor 1 at a low temperature and high viscosity. The lubricating oil is easily caught and can be prevented from flowing out of the compressor unnecessarily. As a result, the amount of lubricating oil mixed with the refrigerant of the refrigeration cycle can be reduced.
[0043]
Fifth, since a bleed passage and an air supply passage formed with a small passage cross-sectional area as in the conventional structure are unnecessary, it is suitable for a refrigeration cycle in which a supercritical fluid (such as carbon dioxide gas) is sealed. In other words, when a supercritical fluid requiring a total refrigerant charge amount of about 1/6 is applied to a compressor having a conventional structure having a passage formed with a minute passage cross section, the passage is six times more precise. Although the cross section needs to be designed, the compressor 1 of this embodiment has a structure suitable for applying a supercritical fluid since there is no such a passage having a small cross section.
[0044]
In the above embodiment, the suction passage 32 communicating the crank chamber 5 and the suction chamber 7 is a through hole formed through the cylinder block 2, the valve plate 9, and the rear housing 6. Alternatively, the suction passage may be formed using a pipe or the like separately provided, and in the above embodiment, the pressure control valve 33 is provided inside the compressor main body, but is arranged outside the compressor main body. You may.
[0045]
In the above embodiment, the pressure control valve 33 is an electromagnetic pressure control valve. However, the pressure control valve may be a mechanical pressure control valve (for example, the mechanical pressure control valve may be a suction chamber pressure, a crank chamber pressure, or a discharge pressure). There is a structure in which a pressure-sensitive portion that mechanically senses room pressure or the like is provided and a valve is opened and closed by the operation of the pressure-sensitive portion.
[Brief description of the drawings]
FIG. 1 is an overall sectional view of a compressor according to a first embodiment of the present invention.
FIG. 2 is a rear view of the rear housing of the compressor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Variable displacement compressor 2 Cylinder block 3 Cylinder bore 4 Front housing 5 Crank chamber 6 Rear housing 7 Suction chamber 8 Discharge chamber 29 Piston 32 Suction passage 33 Electromagnetic pressure control valve (pressure control valve)
REFERENCE SIGNS LIST 100 radiator 200 internal heat exchanger 300 expansion valve 400 evaporator 500 accumulator S drive shaft Ps suction chamber pressure Pd discharge chamber pressure pc crank chamber pressures P1 to P7 Piping

Claims (2)

In a compressor (1) that reciprocates a piston (29) in a cylinder bore (3) to suck and compress refrigerant in a suction chamber (7) into a cylinder bore (3) and discharge it to a discharge chamber (8).
A variable displacement for controlling a piston stroke by adjusting a differential pressure between a crank chamber pressure (Pc) on the rear side of the piston (29) and a suction chamber pressure (Ps) on a front side of the piston (29). A compressor (1),
A suction port (53) for introducing low-temperature and low-pressure refrigerant from the evaporator (400) is provided in the crank chamber (5), and a suction passage (32) communicating the crank chamber (5) with the suction chamber (7). ) To introduce the low-temperature and low-pressure refrigerant from the evaporator (400) into the suction chamber (7) via the crank chamber (5).
A pressure control valve (33) is provided in the suction passage (32) for adjusting a pressure difference between the upstream crank chamber pressure (Pc) and the downstream suction chamber pressure (Ps). Variable capacity compressor (1). A compressor (1) for compressing the refrigerant;
A radiator (100) for radiating heat of the high-temperature and high-pressure refrigerant compressed by the compressor (1); and an expansion valve (300) for controlling the pressure of the low-temperature and high-pressure refrigerant cooled by the radiator (100). A refrigeration cycle in which an evaporator (400) for cooling ventilation air by an endothermic effect of refrigerant whose pressure is controlled by the expansion valve (300) is connected in series with at least a pipe;
The compressor (1) sucks and compresses the refrigerant in the suction chamber (7) into the cylinder bore (3) and discharges it to the discharge chamber (8) by reciprocating a piston (29) in the cylinder bore (3). Variable displacement compression for controlling the piston stroke by adjusting the pressure difference between the crank chamber pressure (Pc) on the rear side of the piston (29) and the suction chamber pressure (Ps) on the front side of the piston (29). Machine (1),
A suction port (53) for introducing low-temperature and low-pressure refrigerant from the evaporator (400) is provided in the crank chamber (5), and a suction passage (32) communicating the crank chamber (5) with the suction chamber (7). ) To introduce the low-temperature and low-pressure refrigerant from the evaporator (400) into the suction chamber (7) via the crank chamber (5).
A pressure control valve (33) is provided in the suction passage (32) for adjusting a pressure difference between the upstream crank chamber pressure (Pc) and the downstream suction chamber pressure (Ps). Refrigeration cycle.

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