JP3322355B2 - Variable displacement compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor suitable for use in vehicle air conditioning, and more particularly, to a compressor having a suction chamber, a discharge chamber and a crank chamber, which regulates a differential pressure between the suction chamber pressure and the crank chamber pressure. The displacement (piston stroke) of the rotary swash plate to control the displacement.

[0002]

2. Description of the Related Art Conventionally, as a variable displacement compressor of this type, for example, a compressor disclosed in Japanese Patent Application Laid-Open No. 61-215468 is known. The compressor has an air supply passage communicating the discharge chamber with the crank chamber, an on-off valve for opening and closing the air supply passage, a bleed passage constantly communicating the suction chamber with the crank chamber, and a crank chamber pressure. When the pressure falls below the set value, the air supply passage is opened by operating the on-off valve in response to the pressure, and when the pressure exceeds the set value, the air supply passage is closed by operating the on-off valve. And a valve control mechanism.

Therefore, in the operating state of the compressor in which the on-off valve closes the air supply passage, blow-by gas leaking from the compression chamber to the crank chamber is always returned to the suction chamber via the bleed passage. Then, when the temperature of the cabin decreases, the cooling load decreases, and when the crank chamber pressure falls below a set value with a decrease in the suction chamber pressure, the valve control mechanism opens the on-off valve to open the high-pressure refrigerant gas from the discharge chamber to the crank chamber. Was introduced,
Increase crankcase pressure. Thereafter, when the crank chamber pressure becomes equal to or higher than the set value, the valve control mechanism closes the on-off valve, closes the air supply passage, and stops increasing the crank chamber pressure. In this manner, the crank chamber pressure is maintained at a substantially set value during the steady operation, and the piston stroke, that is, the discharge capacity, is controlled by the differential pressure between the crank chamber pressure and the suction chamber pressure that follows the fluctuation of the cooling load.

[0004]

However, it is extremely difficult to uniquely determine the sectional area of the bleed passage. For example, in view of recirculating the blow-by gas flowing into the crank chamber to the suction chamber, it is desirable to set the cross-sectional area of the bleed passage as large as possible.
Conversely, when shifting to low capacity operation, the cross-sectional area must be set small to increase the crankcase pressure. In particular, when the load is low and the discharge chamber pressure is extremely low, the crank chamber pressure does not increase unless the cross-sectional area is reduced so much, and the low displacement control is practically disabled. If the cross-sectional area is excessively reduced, the wear of the pistons and cylinder bores will increase, and if the discharge chamber pressure rises excessively during traffic congestion in summer, the increased inflow of blow-by gas will increase the discharge of the bleed passage. There is also a situation in which the crank chamber pressure rises above the capacity, and unintended low-capacity control is performed.

An object of the present invention is to improve the responsiveness of displacement control in the entire control range of a compressor.

[0006]

In order to solve the above-mentioned problems, the present invention comprises a suction chamber, a discharge chamber, and a crank chamber, and adjusts a pressure difference between the suction chamber pressure and the crank chamber pressure to tilt the rotary swash plate. by varying the opening and closing in and to control the discharge capacity variable displacement compressor, the air supply passage communicating with the discharge chamber and the crank chamber, the air supply passage in response to the suction chamber pressure and air supply control valve to a bleed passage connecting the said suction chamber and said <br/> crank chamber, each other in the bleed passage
Wrapping the first and second bleed control valve Ru in parallel arranged to have
The bleed control valve adjusts the flow rate of the bleed passage in response to each of the crank chamber pressure and the discharge chamber pressure .
It has adopted a novel structure which is formed by sea urchin.

[0007] More preferred form of the invention, the first and second bleed control valve, a single bleed control for adjusting the flow rate of the bleed passage in response to both of the crank chamber pressure and the discharge chamber pressure It consists of a valve.

[0008]

Therefore, when the compressor is started, the discharge chamber pressure is low, and the valve hole of the second bleed control valve is reduced.
On the other hand, when the crank chamber pressure exceeds the set value, the valve hole of the first bleed control valve is largely opened, and the crank chamber pressure (P
c) = Operation starts at suction chamber pressure (Ps). Thereafter, while the heat load was large, the crank chamber pressure and the discharge chamber pressure were both high during the low-speed operation, and the valve holes of the first and second bleed control valves were both largely opened. In this case, the discharge is performed without any trouble, and the operation is continued at (Pc) = (Ps). When the operation is shifted to the high-speed operation under the heat load condition, the crank chamber pressure falls below the set value and the valve hole of the first bleed control valve is reduced with the decrease of the suction chamber pressure. By keeping the second bleeding control valve at a medium opening based on this, the blow-by gas discharge function is ensured.

When the pressure in the suction chamber falls below the set value due to the reduction in the heat load, the air supply control valve opens, but the first and second air supply control valves respond to the crank chamber pressure and the discharge chamber pressure. The valve holes of the bleed control valve are both reduced to restrict discharge, and rapid volume change, that is, good responsiveness can be expected.
Further, even in the event of an abnormal situation in which the air supply control valve cannot be closed, since the valve hole of the first bleed control valve is opened to the maximum, an excessive rise in the crank chamber pressure is prevented.

[0010]

EXAMPLES Hereinafter, the embodiments of the present invention will be described with reference to FIG. FIG. 1 is an explanatory view schematically showing the relationship between a variable displacement compressor and a control valve element, and FIGS. 2 to 4 are enlarged sectional views showing details of each control valve. In FIG. 1, 1 is
1 shows a main body forming an outer shell of a variable displacement compressor including a cylinder block and a housing connected thereto, and the main body 1 has a plurality of cylinder bores 2, a suction chamber 3, a discharge chamber 4, and a crank. A chamber 5 is formed,
A drive shaft 6 passing through the inside of the crank chamber 5 is rotatably supported. A rotary swash plate 7 is provided on the drive shaft 6 in the crank chamber 5.
Is supported so as to be displaceable at an angle, and the rotary swash plate 7 is, for example, a piston 8 that linearly moves in the cylinder bore 2 via a shoe or the like.
Moored in Therefore, the rotational motion of the drive shaft 6 is converted into the reciprocating motion of the piston 8 via the swash plate 7, and the refrigerant gas sucked into the cylinder bore 2 from the suction chamber 3 is discharged to the discharge chamber 4 while being compressed. The air is circulated through a condenser 9, an expansion valve 10, and an evaporator 11 that constitute an air conditioning refrigeration circuit. The swash plate inclination angle and the piston stroke changes according to the pressure difference between the crank chamber pressure and the suction chamber pressure, the discharge capacity is variably controlled. The crank chamber pressure is diversifiedly controlled by each control valve (see FIGS. 2 to 4) described below.

That is, a suction pressure chamber 21 and a discharge pressure chamber 22 are provided opposite to each other in the air supply control valve 20 provided in the main body 1, and the suction pressure chamber 21 is connected to the suction chamber through a pressure guiding passage 23. 3
The discharge pressure chamber 22 is communicated with the discharge chamber 4 via an air supply passage 30a. The suction pressure chamber 21 is provided with a bellows 26 which can expand and contract so as to surround an atmospheric pressure chamber 25 arranged at the center.
6 is constantly urged through a spring 27 in the extending direction (toward the discharge pressure chamber 22). On the other hand, the discharge pressure chamber 22 is provided with a valve hole 28 at one end near the suction pressure chamber 21, and a port 29 defined and connected to the valve hole 28 is connected to the crank chamber 5 via the air supply passage 30 b. Are in communication. A base end of a valve rod 31 is connected to the bellows 26 so that the discharge pressure chamber 22
The distal end is provided so as to pass through the port 29 and the valve hole 28 and to reach the inside of the discharge pressure chamber 22. The distal end of the valve rod 31 is opposed to the valve hole 28 so that the valve body 32
The valve body 32 is configured to be openable and closable through the expansion and contraction action of the bellows 26, and the discharge pressure chamber 2
2 is always urged in the direction of the valve hole 28 (closing direction) by the spring 33 interposed. Therefore, when the suction chamber pressure introduced into the suction pressure chamber 21 becomes lower than the set value, the bellows 26 is extended and the valve rod 31 moves forward to open the valve body 32, and the port 29 and the supply port are opened from the valve hole 28. The discharged refrigerant gas is supplied to the crank chamber 5 via the air passage 30b.

Next, the first bleed control valve 40 housed in the main body 1 will be described. The first bleed control valve 40 is provided with a bleed passage 41 communicating with each of the crank chamber 5 and the suction chamber 3.
a, 41b. That is, the first bleed control valve 40 is provided with an atmospheric pressure chamber 43 and a crank pressure chamber 44 opposed to each other with a diaphragm 42 interposed therebetween. The atmospheric pressure chamber 43 has one end connected to the diaphragm 42 and a spring 45 interposed therebetween. On the other hand, a valve hole 46 is opened in the crank pressure chamber 44, and the crank pressure chamber 44 has an bleed passage 41a connected to the crank chamber 5, and the valve hole 46 has a bleed passage 41b connected to the suction chamber 3.
Has been communicated with. A base end of the crank pressure chamber 44 is connected to the diaphragm 42, and a valve body 47 whose front end is opposed to the valve hole 46 is provided so as to be able to advance and retreat, and one end is connected to the diaphragm 4.
The normal opening of the valve hole 46 is set by the urging force of the spring 48 connected to the second valve 2. Therefore, when the crank chamber pressure introduced into the crank pressure chamber 44 rises above the set value, the opening of the valve hole 46 in which the valve body 47 retreats together with the diaphragm 42 expands, and the bleed passage 41a moves from the bleed passage 41a to the same 41b. The flow rate of the recirculated refrigerant gas is increased.

Next, the second bleed control valve 60 provided in the main body 1 will be described. The second bleed control valve 60 is interposed between the bleed passages 41 a and 41 c provided in parallel with the bleed passages 41 a and 41 b and the pressure guiding passage 62 communicating with the discharge chamber 4. A valve base 63 is inserted into a storage chamber formed from the outer wall of the main body 1, and the bleed passage 4
1a and 41c are mutually connected via a valve hole 64 formed in the valve base 63 and an intermediate chamber 65. The valve hole 64
The spool valve element 66 that is movable and supported by the intermediate chamber 65 extends from the intermediate chamber 65 to the control pressure chamber 67, and the integrally formed flange plate 66 a is pressed by the biasing force of the spring 68. The normal opening of the valve hole 64 is set by abutting against the end wall of the control pressure chamber 67. And, in the control pressure chamber 67 which is communicated with the pressure guiding passage 62,
Surrounding the spring 68, both ends of the spring 68
A bellows 70 fluid-tightly connected to the cover plate 69 of the pressure chamber 6 a and the control pressure chamber 67 is housed therein, and the inside of the bellows 70 is communicated with the atmosphere through a through hole 71 formed through the cover plate 69. . Therefore, when the pressure of the discharge chamber introduced into the control pressure chamber 67 rises above the set value, the bellows 70 contracts together with the spring 68 and pulls back the spool valve element 66, and the valve hole 6
The flow rate of the refrigerant gas recirculated from the bleed passages 41a to the bleed passages 41c is increased by expanding the opening degree of the flow path 4.

This embodiment is configured as described above.
When the compressor is stopped, the pressure in the machine is balanced at a pressure higher than the set suction chamber pressure.
The pressure of the suction pressure chamber 21 formed in the pressure
7, the bellows 26 is contracted by exceeding the combined force of
2 is seated in the valve hole 28 by the urging force of the spring 33, and the air supply passage 30b is kept closed. When the drive shaft 6 is rotated from this state via an electrode clutch (not shown),
The rotational swing of the rotary swash plate 7 is converted into a reciprocating motion of the piston 8, and the compression work is started.

When the compressor is started, the discharge chamber pressure is low, and the spool valve element 66 of the second bleed control valve 60 maintains the valve hole 64 at the reduced normal opening by the urging force of the spring 68. On the other hand, the crank chamber pressure exceeds the set value, and the valve body 47 of the first bleed control valve 40 retreats together with the diaphragm 42 to expand the opening of the valve hole 46, so that the bleed from the crank chamber 5 is smooth. The operation is started with the crank chamber pressure (Pc) = the suction chamber pressure (Ps). Thereafter, while the heat load is large, the crank chamber pressure and the discharge chamber pressure are both high during low-speed operation, and the second bleed control valve 60
Of the first and second bleeding control valves 40 and 60 are also retracted.
Since both 6 and 64 are in the expanded state, even if the blow-by gas amount increases, it is discharged without any support and the operation is continued at (Pc) = (Ps). When the operation is shifted to the high-speed operation under the heat load condition, the crank chamber pressure falls below the set value as the suction chamber pressure decreases, and the valve body 47 of the first bleed control valve 40
And the spool valve body 66 of the second bleed control valve 60 maintains the opening of the valve hole 64 at a medium level based on the discharge chamber pressure. In addition, the function of discharging blow-by gas is ensured.

When the pressure in the suction chamber falls below the set value due to a reduction in the heat load, the bellows 26 in the air supply control valve 20 is extended and the valve rod 31 moves forward to open the valve body 32, thereby opening the valve hole. The discharge refrigerant gas is supplied from 28 to the crank chamber 5 via the port 29 and the air supply passage 30b. At this time, the discharge chamber pressure is low, and the crank chamber pressure is also near the set value. Therefore, the first and second bleed control valves 40,
Each of the valve holes 46 and 64 of the 60 is reduced in size to regulate discharge, and quick displacement control is performed with good responsiveness. Further, even when an abnormal situation occurs such that the air supply control valve 20 cannot be closed, the valve hole 4 of the first bleed control valve 40 is
6 is opened to the maximum extent, so that an excessive rise in the crankcase pressure is prevented.

Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the first and second bleed control valves 40 and 60 are operated independently of the crank chamber pressure and the discharge chamber pressure to adjust the flow rate of the refrigerant gas discharged from the bleed passage 41a. It has a feature in that it is constituted by the bleed control valve, and detailed description of the remaining structure is omitted to avoid duplication.

The bleed control valve 80 is interposed between bleed passages 41 a and 41 d communicating with the crank chamber 5 and the suction chamber 3, respectively, and a pressure guiding passage 82 communicating with the discharge chamber 4. A valve base 83 is inserted into a storage chamber formed from the outer wall of the main body 1, and the valve base 83 is formed in a hollow cylindrical shape with a stepped hole, and an upper end (left end in the drawing) is a lid 84. The lower end (right end in the figure) is closed by a floor 86 including an adjustable spring seat 85. The stepped hole has a second pressure guiding chamber 87 communicating from the upper end to the pressure guiding passage 82, a first pressure guiding chamber 88 communicating with the bleed passage 41a, a first valve hole 89, and the bleed passage 41.
d, and is partitioned into a first bleeding chamber 90 communicating with the first bleeding chamber 9.
The first valve body 91 is fitted in the inside of 0. The first valve body 9
Reference numeral 1 denotes a guide portion which is in close contact with the inner wall of the first bleeding chamber 90, a small-diameter portion which forms a substantially annular first bleeding chamber 90 between the inner wall, and the first valve connected to the small-diameter portion. A taper valve portion 91a for adjusting the opening degree of the hole 89;
Reference numeral 1 denotes a second valve hole 91 opened at the tip of the tapered valve portion 91a.
Hollow second bleed chamber 9 whose diameter is greatly expanded except for part b
2 is provided. Note that the first bleed chamber 91 and the second bleed chamber 92 are communicated with each other through a through-hole 91c.

In the first pressure guiding chamber 88, a differential pressure piston 9 is provided.
3, the enlarged diameter head 93a of the differential pressure piston 93 extends into the second pressure guiding chamber 87, and the enlarged diameter head 93a is connected to the mouth end of the first pressure guiding chamber 88. An abutting sealing taper wall is formed. A rod-shaped second valve body 94 is connected to the body of the differential pressure piston 93. The second valve body 94 has a spring seat 95 mounted on an extending end thereof passing through the second valve hole 91b. In addition, a tapered valve portion 94a for adjusting the opening degree of the second valve hole 91b is formed at an intermediate portion thereof. The first valve body 91 is a first spring 96, and the second valve body 94 is a second spring 96.
The first valve hole 89 and the second valve hole 9 are respectively formed by the spring 97.
1b is reduced.

The bleed control valve 80 of the present embodiment is configured as described above. When the crank chamber pressure guided from the bleed passage 41a to the first pressure guiding chamber 88 exceeds a set value, the first valve body 91 is activated. When the tapered valve portion 91a is separated from the first valve hole 89 by retreating against the urging force of the first spring 96, the first
The flow passage between the pressure guiding chamber 88 and the first bleeding chamber 90 is expanded (FIG. 6). On the other hand, when the pressure in the discharge chamber led from the pressure guiding passage 82 to the second pressure guiding chamber 87 exceeds the set value, the differential pressure piston 9
3, the second valve body 94 advances against the urging force of the second spring 97, and the tapered valve portion 94a is displaced in the axial direction with respect to the second valve hole 91b. The flow passage connecting the first pressure guiding chamber 88 and the second bleeding chamber 92 is expanded (FIG. 7).

As described above, the first valve body 9 of the bleed control valve 80
The element including 1 corresponds to the first bleed control valve 40 of the first embodiment, and the element including the second valve body 94 also corresponds to the second bleed control valve 60. Therefore, during the high-speed operation described above, the operation of the second valve body 94 assists the first valve body 91 to secure the bleeding ability. The operation of the first valve body 91 is
Assists 4 and demonstrates sufficient bleeding ability.

[0022]

As described above, in the variable displacement compressor according to the present invention, the bleeding flow rate from the crank chamber is diversified by the bleed control valve element responsive to both the crank chamber pressure and the discharge chamber pressure. Because it is controlled.
Abnormal pressurization of the crank chamber can be steadily prevented, and excellent capacity control responsiveness can be ensured even when the discharge chamber pressure is low.

Further, when the bleeding control valve element is configured as a single control valve, it can contribute more effectively to the compactness and simplification of the compressor.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing a relationship between a variable displacement compressor and a control valve element according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing an air supply control valve.

FIG. 3 is an enlarged sectional view showing a first bleed control valve;

FIG. 4 is an enlarged sectional view showing a second bleed control valve;

FIG. 5 is an explanatory view schematically showing a relationship between a variable displacement compressor and a control valve element according to a second embodiment of the present invention.

Figure 6 is an enlarged cross-sectional view showing an operation mode of the extracted air control valve

Figure 7 is an enlarged cross-sectional showing another operation form of extracted air control valve view

[Explanation of symbols]

Reference numeral 3 denotes a suction chamber, 4 denotes a discharge chamber, 5 denotes a crank chamber, 7 denotes a rotary swash plate, 20 denotes an air supply control valve, 23 denotes a pressure guiding passage, 30a and 30
b is an air supply passage, 40 is a first bleed control valve, 41a, 41
b, 41c, 41d are bleed passages, 60 is a second bleed control valve, 62 is a pressure guide passage, 80 is a bleed control valve, and 82 is a pressure guide passage.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-23385 (JP, A) JP-A-62-253970 (JP, A) JP-A-61-215468 (JP, A) 99985 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 27/08 F04B 27/14 F04B 39/10

Claims (2)

(57) [Claims] A suction chamber, a discharge chamber, and a crank chamber;
Rotating swash plate by adjusting the differential pressure between the entrance pressure and the crankcase pressure
To control the discharge capacity by changing the tilt angle of
The variable capacity compressor  With the above discharge chamberthe aboveAn air supply passage communicating with the crank chamber;
the aboveAir supply system that opens and closes the air supply passage in response to suction chamber pressure
The valve and the above suction chamberthe aboveBleed air communicating with the crankcase
A passage and the bleed passageInside each otherAre arranged in parallelFirst
And a second bleed control valve, wherein the bleed control valve isK
The extraction is performed in response to the rank chamber pressure and the discharge chamber pressure.
Adjust the flow rate in the air passagelikeVariable capacity compression
Machine. Wherein said first and second bleed control valve, the class <br/> ink chamber pressure and bleed control valve alone configuration for adjusting the flow rate of the bleed passage in response to both the discharge chamber pressure The variable displacement compressor according to claim 1, wherein