JP2600317B2 - Variable capacity compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a variable displacement compressor used for vehicle air conditioning or the like, and more particularly, to a variable displacement compressor having a suction chamber and a crank chamber. The present invention relates to an oscillating plate type variable displacement compressor in which a piston stroke changes in accordance with a differential pressure of the compressor to control a compression displacement.

[Prior Art] Generally, in a swinging plate type variable displacement compressor, a plurality of cylinder chambers are provided in parallel along a circumferential direction, and a piston inserted into each cylinder chamber is swung by a swinging plate. Is provided so as to obtain a compressing action by continuously moving back and forth. The oscillating plate is provided so that the oscillating inclination angle can be changed in accordance with the change in the cooling load in the vehicle compartment. In other words, a large compression capacity can be obtained by increasing the rocking inclination angle of the rocking plate when the cooling load in the vehicle compartment is large, and the rocking of the rocking plate when the cooling load in the vehicle compartment is small. It is provided so that a small compression capacity can be obtained by reducing the inclination angle. Conventionally, as one of the methods for changing the swing inclination angle, a closed crank chamber is provided, and when the cooling load is large, the crank chamber pressure is maintained at a set pressure (suction pressure) and the swing is performed. In addition to obtaining a state in which the plate swings with a large inclination angle, when the cooling load decreases, the discharge gas is guided into the crank chamber to increase the crank chamber pressure, and the swing plate There has been proposed a method of obtaining a state of swinging with a small inclination angle.

FIG. 3 is a drawing showing the specific structure, in which supply passages c and d for discharge pressure are formed and communicated between the discharge chamber a and the crank chamber b, and between the supply passages c and d. An on-off valve e is provided interposed therebetween. The opening / closing valve e is provided with a discharge pressure chamber f communicating with the air supply passages c and d and a suction pressure chamber h communicating with the suction chamber g so as to face each other. A bellows j is extendably built in with a pressure chamber (atmospheric pressure chamber) i communicating therewith, while the opening / closing valve k of the air supply passages c and d is provided in the discharge pressure chamber f with the bellows j.
It can be opened and closed in conjunction with the expansion and contraction of In a state where the cooling load in the vehicle interior is large, the bellows j contracts by obtaining a state where the suction pressure in the suction pressure chamber h exceeds the set pressure in the atmospheric pressure chamber i (atmospheric pressure + the urging pressure of the spring l). To close the air supply passages c and d,
That is, a state where the inside of the crank chamber b is in the suction pressure state and the swing plate is swung with a large inclination angle is obtained, and the compression action of the maximum capacity is obtained by increasing the piston stroke. On the other hand, in a state where the cooling load in the vehicle interior is reduced, a state is obtained in which the suction pressure in the suction pressure chamber h is lower than the set pressure in the atmospheric pressure chamber i (atmospheric pressure + the urging pressure of the spring l). The supply passages c and d are opened through the extension action, and the discharge pressure is reduced to the crank chamber b.
The pressure inside the crank chamber b is suddenly increased by feeding it into the inside, and the swinging plate is changed into a state of swinging with a small inclination angle, and the compression stroke is reduced by reducing the piston stroke. Is provided so that An escape passage n is formed by communicating between the crank chamber b and the suction chamber g, and discharge gas (blow-by gas) flowing into the crank chamber b from a gap formed between each cylinder chamber 0 and the piston p is sucked. It is provided so that it can escape to the chamber g. That is, the blow-by gas is released to the suction chamber g to prevent the pressure increase due to the blow-by gas in the cranking chamber b and to maintain the inside of the crank chamber b at the set pressure.

[Problems to be Solved by the Invention] However, in the conventional variable displacement compressor as described above, the degree of opening of the on-off valve is adjusted by expansion and contraction of pressure sensing means such as a blow. This changes the pressure in the crank chamber to control the tilt angle (stroke of the piston) of the rocking plate. In this case, since the pressure control point of the pressure sensing means is set to the determined value, the suction pressure is controlled to a fixed constant value as a result.

Therefore, even if there is a request to perform a low-capacity compression operation at the time of acceleration or the like, the pressure set value of the pressure sensing means cannot be changed.

An object of the present invention is to solve the problem that it is possible to arbitrarily control the pressure in the crank chamber and, consequently, the compression capacity by modifying the valve control means for controlling the crank chamber.

Means for Solving the Problems In order to solve the above problems, the present invention provides a valve control unit provided in an air supply passage communicating a crank chamber and a discharge chamber,
Technical means is provided in which the pressure control point of the pressure-sensitive means for controlling the on-off valve is varied via the variable load input means.

That is, in the variable displacement compressor of the present invention, valve control means is provided in an air supply passage communicating the crank chamber and the discharge chamber in order to positively change the pressure in the crank chamber. The timing and amount of discharge gas introduced from the discharge chamber into the crank chamber can be controlled arbitrarily.

[Operation] The variable displacement compressor according to the present invention is designed such that, when the suction pressure is not so small, for example, when it is desired to increase the pressure in the crank chamber and reduce the compression capacity, the variable load input means is applied to the pressure sensing means of the valve means. In addition, by increasing the pressure control point of the pressure sensing means, the opening operation of the on-off valve can be enabled.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

(Embodiment 1) This embodiment is embodied in an oscillating plate type variable displacement compressor used in a vehicle air conditioner. As shown in FIG. The rear housing 3 is joined and fixed via a valve plate 2 by a suitable fastening means. An annular suction chamber 4 is formed in the outer peripheral portion of the rear housing 3, and a discharge chamber 5 is formed in the center of the rear housing 3. The suction chamber 4 is formed through a suction port and a discharge port (not shown). Connected to the external cooling circuit. A front housing 6 is joined and fixed to the left end surface of the cylinder block 1, and a crank chamber 7 is formed therein. A drive shaft 8 is rotatably supported on the cylinder block 1 and the front housing 6 by a pair of bearings 9 and a shaft seal mechanism 19.

Five cylinder chambers 10 are formed in the cylinder block 1 so as to extend through both ends thereof in parallel with the drive shaft 8. A piston 11 is mounted in each cylinder chamber 10 so as to be capable of reciprocating sliding, and a piston rod 12 is connected to the left end surface thereof. The valve plate 2 includes a suction chamber 4 and the respective syringe chambers.
Suction valves 13 for introducing refrigerant gas into the 10 compression chambers are formed. Similarly, the valve plate 2 has cylinder chambers.
A discharge valve 14 is provided for leading the refrigerant gas compressed in the 10 compression chambers to the discharge chamber 5.

A rotating body 15 is fitted and fixed to the drive shaft 8.
A swinging plate 17 is tiltably connected to 15 by a connecting pin 16, and its rotation is regulated by a guide rod 18 laid horizontally at a fixed position. Each of the piston rods is
When the left end of 12 is connected to each other and the rotating body 15 is rotated by the rotation of the drive shaft 8 and the rocking plate 17 is tilted, the piston 11 reciprocates via the piston rod 12. I have. Then, the piston stroke changes according to the change in the suction pressure of the suction chamber 4, so that the inclination angle of the rocking plate 17 changes, and the compression capacity is controlled.

The configuration described above is the same as that of the conventional variable displacement compressor.

Next, the main part of the present invention will be described.
A first housing is formed in the rear housing 3 for partitioning and forming the suction chamber 4.
A valve means 30 is provided, and the pressure is controlled in the crank chamber 7 by opening and closing the first valve means 30. That is, the first valve means 30 is provided with a suction pressure chamber 31 and a discharge pressure chamber 32 opposed to each other. The suction pressure chamber 31 is connected to the suction chamber 4 via the communication passage 4a, and the discharge pressure chamber 32 is The discharge chamber 5 is provided so as to communicate with the discharge chamber 5 via an air passage 5a (a discharge pressure supply passage). And suction pressure chamber
A pressure-sensitive chamber 33 communicating with a second valve means 50 to be described later is provided on the face 31 and a diaphragm 34 is provided between the two chambers 31 and 33. A spring 35 is interposed in the pressure sensing chamber 33, and the diaphragm 34 is always in the discharge pressure chamber.
It is provided so as to be urged in 32 directions.
On the other hand, the discharge pressure chamber 32 has a valve seat at one end near the suction pressure chamber 31.
A port 39 is provided and a port 39 is defined through the valve seat 36. An air supply passage 7a of discharge pressure extends from the port 39, and its tip is provided so as to face the crank chamber 7. Further, one end of a valve rod 40 is connected to the above-described diaphragm 34, and the valve rod 40 extends toward the discharge pressure chamber 32, and the distal end portion of the valve rod 40 is discharged through the port 39 and the valve seat 36. The pressure chamber 32 is provided so as to face the inside. A conical on-off valve 37 is fitted to the distal end of the valve rod 40 so as to move forward and backward in correspondence with the valve seat 36. That is, the on-off valve 37 is provided so that it can be opened and closed via the advancing and retreating action of the diaphragm 34. Further, one end of the discharge pressure chamber 32 is
, A spring 41 is interposed, and is provided so as to urge the on-off valve 37 toward the valve seat 36 (close direction).

The rear housing 3 has a crank chamber 7 and a suction chamber 4.
And a blow-by gas escape passage 20a for communicating with the blow-by gas. A throttle valve or the like (not shown) is provided in the middle of the relief passage 20a.

A communication passage 50a is provided from the pressure-sensitive chamber 33. The communication passage 50a is connected via a second valve means 50 to a communication passage 50b communicating with the atmospheric pressure and a communication passage 50c extending to the discharge chamber 5. And each is in communication. The second valve means 50 is for selectively communicating between the communication path 50a from the pressure sensing chamber 33 and the communication path 50b communicating with the atmospheric pressure or the communication path 50c from the discharge chamber 5. Directional control valve, electromagnetic three-way valve, etc. can be used.

Next, the operation of the variable displacement compressor configured as described above will be described.

When the compressor is stopped, the second valve means
50 opens the communication passages 50a and 50b, and the pressure-sensitive chamber 33 communicates with the atmospheric pressure. In the first valve means 30, the diaphragm 34 has a pressure difference (pressure in the suction pressure chamber 31> atmospheric pressure + spring).
35 (hereinafter, “atmospheric pressure + urging force of spring 35” is referred to as “set pressure”), and is retracted toward pressure-sensitive chamber 33 (valve seat 36 is closed by on-off valve 37 and discharge pressure chamber 32 The air supply passage 7a that connects between the engine and the crank chamber 7 is in a closed state).
That is, the crank chamber 7 is in communication with the suction chamber 4 (a state in which the suction pressure is maintained), and a large swing inclination angle is obtained in the swing plate 17.

When the drive shaft 8 is rotated by the power of the engine or the like in this state, when the cooling load in the vehicle interior is large, the swing plate 17 swings with a large swing inclination angle, and the piston 11 has a large stroke. Reciprocating to perform a large capacity compression operation.

When such a large-capacity operation is performed for a certain period of time, the cabin is cooled and the cooling load (evaporator heat load) is reduced.
Therefore, the suction pressure of the refrigerant gas sent to the hopper decreases. When the suction pressure falls below the "set pressure" in the first valve means 30, the pressure difference causes the diaphragm 34 to be pushed out toward the suction pressure chamber 31 to open the on-off valve 37. When the on-off valve 37 is opened in this manner, the air supply passage 7a connecting the discharge pressure chamber 31 and the crank chamber 7 is opened, and the discharge gas in the discharge chamber 5 is sent into the crank chamber 7. It is. The discharge gas is thus sent into the crank chamber 7 and the pressure in the crank chamber 7 rises, thereby reducing the stroke of each piston 11, that is, the swing plate
The effect of gradually reducing the compression capacity by reducing the swing inclination angle of 17 can be obtained.

The operation described above is the same as the operation of the conventional variable displacement compressor.

Next, an operation specific to the compressor of the present embodiment will be described. As described above, the second valve means 50 opens the communication passage 50a and the communication passage 50b in the normal compression operation, and the pressure-sensitive chamber 33 in the first valve means 30 communicates with the atmospheric pressure. here,
When it is desired to arbitrarily reduce the compression capacity during acceleration or the like, a voltage signal is externally supplied to the second valve means 50 via an amplifier to close the communication passage 50a and the communication passage 50b, and at the same time, the communication passage 50b
a and the communication passage 50c are opened. Thereby, the first valve means 30
The pressure-sensitive chamber 33 communicates with the discharge chamber 5 so that the discharge gas is
And the “set pressure” is displaced. That is, even if the suction pressure (the pressure in the suction pressure chamber 31) is constant, the pressure control point of the diaphragm 34 is displaced by the pressure increase in the pressure-sensitive chamber 33 due to the introduction of the discharge gas as described above. Then, the on-off valve 37 can be opened by pushing the diaphragm 34 toward the suction pressure chamber 31.

Therefore, the variable displacement compressor of the present embodiment has the discharge chamber 5
The control of the timing and the amount of discharge gas to be introduced into the crank chamber 7 from above can be arbitrarily performed, whereby the pressure in the crank chamber 7 can be increased and the low-volume compression operation can be performed as necessary.

Second Embodiment In the first embodiment, the suction pressure chamber 31 and the pressure-sensitive chamber 33 are separated by a diaphragm 34, and the pressure-sensitive chamber 33 communicates with the atmospheric pressure during a normal compression operation. For this reason, when the diaphragm 34 is rattled due to long-term use of the compressor, or when the switching between the discharge chamber and the atmospheric pressure is repeated and the high-pressure gas pressure and the atmospheric pressure are repeatedly applied to the diaphragm 34, However, there is a possibility that the suction gas in the suction pressure chamber 31 gradually leaks into the pressure sensing chamber 33 from there, resulting in a problem that the suction gas leaks into the atmosphere.

The second embodiment takes this point into consideration, and as shown in FIG. 2, the communication passage 50a from the pressure sensitive chamber 33 is connected to the second valve means 5.
Through 0 ', the communication passage 50b' extends to the suction chamber 4 and the communication passage 50c extends to the discharge chamber 5, respectively. Also, the spring coupled to the diaphragm 34
35 is inserted into the suction pressure chamber 31 side, and the diaphragm 34 is constantly urged in the direction of the pressure sensing chamber 33. The other specific structure is the same as that of the first embodiment.

 Hereinafter, the specific operation of the second embodiment will be described.

In the second embodiment, the second valve 5
0 'closes the communication between the communication path 50a, the communication path 50b' and the communication path 50c. That is, the pressure-sensitive chamber 33 is in a closed state,
At this time, the diaphragm 34 is retracted in the direction of the pressure sensing chamber 33 due to the pressure difference (the pressure of the suction pressure chamber 31 + the urging force of the spring 35> the pressure of the pressure sensing chamber 33) (the valve seat 36 is closed by the on-off valve 37). State). When the large-capacity operation is performed for a certain period of time after the engine is started, and the cooling load is reduced to lower the suction pressure, the pressure difference (the pressure of the suction pressure chamber 31 + the spring
The diaphragm 34 is pushed out in the direction of the suction pressure chamber 31 by the urging force of 35 <the pressure of the pressure sensing chamber 33), and the on-off valve 37 is opened, so that the operation is changed to the small capacity operation.

Next, when it is desired to arbitrarily reduce the compression capacity during acceleration or the like, a voltage signal is applied to the second valve means 50 'to open the communication passages 50a and 50c in the same manner as in the first embodiment.
The high-pressure gas in the discharge chamber 5 is sent into the pressure-sensitive chamber 33, and the diaphragm 34 is pushed in the direction of the suction pressure chamber 31 to open the on-off valve 37. Then, when returning to the normal compression operation from this state, in the second embodiment,
Then, the communication path 50a and the communication path 5 are temporarily operated by the second valve means 50 '.
0b ', and the suction chamber 4 communicates with the pressure-sensitive chamber 33 for a certain period of time. Then, the communication between the communication path 50a, the communication path 50b', and the communication path 50c is closed to close the pressure-sensitive chamber 33. I do. Therefore, during the normal compression operation, the pressure in the pressure-sensitive chamber 33 is maintained at the suction pressure just before the pressure-sensitive chamber 33 is closed.

As described above, in the second embodiment, the pressure-sensitive chamber 33 is in one of the closed state, the state communicating with the suction chamber 4, and the state communicating with the discharge chamber 5, and the pressure-sensitive chamber 33 is Example 1
It does not communicate with atmospheric pressure as in. Therefore, the compression capacity can be arbitrarily controlled in the same manner as in the first embodiment without the intake gas leaking into the atmosphere.

In the first and second embodiments, the second valve means 50 (50 ') can be arbitrarily controlled by an external signal, and a high pressure gas pressure is applied to the back of the diaphragm 34 to control the pressure control point of the diaphragm. The means for displacing the pressure control point of the diaphragm by applying a load to the back surface of the diaphragm is not limited to the above-described embodiment, and the electromagnetic attraction force of the electromagnetic solenoid or the driving force of the servomotor is used. , A variable load may be applied directly to the back surface of the diaphragm, and the electromagnetic solenoid or the servomotor may be controlled by an external input such as a voltage signal.

[Effects of the Invention] As described above in detail, the variable displacement compressor of the present invention is configured such that, in the valve control means provided in the air supply passage communicating the discharge chamber and the crank chamber, By making the pressure control point of the pressure-sensitive means for controlling the on-off valve displaceable, valve control of the on-off valve can be made optional, whereby the amount of discharge gas introduced from the discharge chamber to the crank chamber and The introduction time can be arbitrarily controlled. Therefore, according to the variable displacement compressor of the present invention, it is possible to perform any compression displacement control such as reducing the compression displacement during acceleration or the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an entire variable displacement compressor according to an embodiment of the present invention. FIG. 2 is a sectional view showing a main part of a capacity compressor according to another embodiment of the present invention. Third
FIG. 1 is a sectional view showing the whole of a conventional variable displacement compressor. 4 ... suction chamber, 5 ... discharge chamber 7 ... crank chamber, 11 ... piston 17 ... rocking plate, 30 ... first valve means 31 ... suction pressure chamber, 32 ... discharge pressure chamber 33 ... … Pressure sensing chamber, 34… Diaphragm 35… Spring, 36… Valve seat 37… Open / close valve, 40… Valve rod 41… Spring, 50… Second valve means

Claims (1)

(57) [Claims] A suction chamber, a discharge chamber, and a crank chamber;
Through a valve control means provided in an air supply passage communicating the discharge chamber and the crank chamber, the compression capacity is controlled by changing the inclination angle of the oscillating plate in accordance with a change in suction pressure. In the variable displacement compressor, the valve control means includes an on-off valve for opening and closing the air supply passage;
A pressure-sensitive means coupled to the on-off valve for detecting the suction pressure and controlling the on-off valve; and a variable load input for applying a variable load to the pressure-sensitive means to make the pressure control point of the pressure-sensitive means variable. And a variable capacity compressor.