JPH0249976A - Variable displacement compressor - Google Patents

Abstract

PURPOSE:To enable a flow amount, timing and the compression volume to be arbitrarily controlled of delivery gas introduced to a crank chamber from a delivery chamber by displacing a pressure control point of a pressure sensing means, controlling an opening and closing valve, through a variable load input means. CONSTITUTION:When a drive shaft 8 is rotated, a swivel plate 17 swivels, and a piston 11 performs a reciprocating motion compressing cooling gas. Here in acceleration or the like, when the compression volume is decreased, a voltage signal from the outside is given to the second valve means 50 through an amplifier. And by closing a communication path 50b for a communication path 50a while by opening a communication path 50c, the first valve means 30 connects its pressure sensing chamber 33 to communicate with a delivery chamber 5, introducing delivery gas to the pressure sensing chamber 33. That is, a pressure control point of a diaphragm 34 is displaced by increasing a pressure in the pressure sensing chamber 33 even in a condition that a fixed pressure is generated in a suction pressure chamber 31. Thus, the diaphragm 34 is pressed in a direction of the suction pressure chamber 31, opening an opening and closing valve 37.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a variable capacity compressor used for vehicle air conditioning, etc., and in particular, it is provided with a suction chamber and a crank chamber, and has a suction pressure and a crank chamber pressure. This invention relates to a wobble plate type variable capacity compressor that controls compression capacity by changing the piston stroke according to the differential pressure of the compressor.

[Prior art 1] In general, a rocking plate type variable capacity compressor has a small number of cylinder chambers arranged in parallel along the circumferential direction, and the pistons inserted into each cylinder chamber are moved by the rocking plate. It is provided so as to obtain a compression effect by moving it continuously forward and backward through motion. The swing plate is provided so that its swing vJ inclination angle can be changed in response to changes in the cooling load in the vehicle interior. In other words, when the cooling load in the single cabin is large, a large compression capacity can be obtained by increasing the swinging angle of the swinging plate, and when the cooling load inside the conductor is small, the swinging plate can be increased. By reducing the angle of inclination, a small compression capacity can be achieved. Conventionally, one method of changing the swing inclination angle is to have a sealed crank chamber, which requires a large cooling load. In this state, the crank chamber pressure is maintained at the set pressure (suction pressure), and the rocking plate swings at a large angle of inclination. A method has been proposed in which the pressure in the crank chamber is increased by introducing discharge gas into the chamber so that a state in which the rocking plate swings at a small angle of inclination is obtained.

FIG. 3 is a drawing showing its specific structure, and shows the air supply passage c for the discharge pressure, which communicates between the discharge chamber a and the crank chamber.
, d are formed, and an on-off valve e is provided interposed between the air supply passage CXd. The circumferential closing valve e is provided with a discharge pressure chamber f communicating with the air supply passage c1d and a suction pressure chamber m communicating with the suction chamber q, facing each other, and the suction pressure chamber communicating with the atmosphere. There is a pressure chamber (atmospheric pressure chamber) i in communication with which a bellows j is built in so that it can expand and contract, while a discharge pressure chamber f has on-off valves k for the air supply passages c and d that are connected to the expansion and contraction of the bellows j. It can be opened and closed freely. When the cooling load in the passenger compartment is large, the suction pressure in the suction pressure chamber exceeds the set pressure in the atmospheric pressure chamber i (atmospheric pressure + the biasing pressure of the spring Ω), causing the bellows j to contract. A state is obtained in which the air supply passages c and d are closed, that is, the inside of the crank chamber is under suction pressure, and the rocking plate is rocked at a large angle of inclination, thereby increasing the piston stroke. This reduces the maximum capacity compression action by 11. On the other hand, when the cooling load in the middle chamber is reduced, the suction pressure in the suction pressure chamber becomes lower than the set pressure in the atmospheric pressure chamber i (atmospheric pressure + the biasing pressure of the spring ρ), so that the bellows j By opening the air supply passage C1d through the expansion action and feeding the discharge pressure into the crank chamber, the pressure inside the crank chamber is rapidly increased and the rocking plate is rocked at a small angle of inclination. The piston is designed to reduce the compression capacity by changing the piston stroke to a smaller piston stroke. In addition, a relief passage n is formed in communication between the crank ib and the suction chamber 9, and the discharge gas (
blow-by gas) can be released into the suction chamber 9. That is, by releasing the blow-by gas to the suction chamber 9, the pressure in the crank chamber can be prevented from increasing due to the blow-by gas, and the pressure in the crank chamber can be maintained at a set pressure.

[Problem to be solved by the invention] However, in the conventional variable displacement compressor as described above,
The opening degree of the on-off valve is adjusted by the expansion and contraction of pressure-sensitive means such as bellows, which changes the pressure in the crank chamber and controls the tilt angle of the rocking plate (the stroke of the piston). ing. In this case, since the pressure control point of the pressure sensitive means is set to a predetermined value, the suction pressure is consequently controlled to a fixed constant value.

Therefore, even if there is a desire to perform low capacity compression operation during acceleration or the like, it has not been possible to respond to this request because the pressure setting value of the pressure sensing means cannot be changed.

A technical problem to be solved by the present invention is to make it possible to arbitrarily control the pressure in the crank chamber, and thus the compression capacity, by modifying the valve control means that controls the inside of the crank chamber.

[Means for Solving the Problems 1] In order to solve the above-mentioned problems, the present invention provides a method for controlling an on-off valve via a variable load input means in a valve control means provided in an air supply passage communicating between a crank chamber and a discharge chamber. A technical measure has been taken to make the pressure control point of the pressure sensitive means variable.

That is, in the variable displacement compressor of the present invention, a valve control means is provided in the air supply passage communicating the crank chamber and the discharge chamber in order to actively change the crank chamber pressure.
The opening/closing valve in the m means can be arbitrarily controlled, so that the introduction timing and amount of the discharge gas introduced from the discharge chamber into the crank chamber can be arbitrarily controlled.

[Function] In the variable capacity compressor of the present invention, when the suction pressure is not so low and it is desired to increase the pressure in the crank chamber to reduce the compression capacity, the variable load input means applies a load to the pressure means of the valve means. By adding this and widening the pressure control point of the pressure sensitive means, the opening operation of the on-off valve can be made possible.

[Example] Embodiments of the present invention will be described below based on the drawings.

(Example 1) This example is a concrete example of a swing plate type variable capacity compressor used in a vehicle air conditioner.As shown in FIG. A rear housing 3 is joined and fixed via the valve plate 2 by appropriate tightening means. An annular suction chamber 4 is provided on the outer periphery of the rear housing 3.
However, a discharge chamber 5 is defined in the center of the rear housing 3 and connected to an external cooling circuit via an inlet and a discharge outlet (not shown). A front housing 6 is fixedly connected to the left end surface of the cylinder block 1, and a crank chamber 7 is formed inside the front housing 6. A drive shaft 8 is rotatably supported by a pair of bearings 9 and a shaft seal mechanism 19 on the cylinder block 1 and the front housing 6.

The cylinder block 1 has 5 holes extending through the cylinder block 1 between both ends thereof.
The cylinder chambers 1o are formed parallel to the drive shaft 8. A piston 11 is mounted in each cylinder chamber 10 so as to be able to slide back and forth, and a piston rod 12 is connected to the left end surface of the piston 11 . Suction valves 13 for introducing refrigerant gas from the suction chamber 4 into the compression chambers of the respective cylinder chambers 10 are formed in the valve plate 2, respectively. Similarly, the valve plate 2 is provided with a discharge valve 14 for guiding the refrigerant gas compressed in the compression chamber of each cylinder chamber 10 to the discharge chamber 5.

A rotary body 15 is fitted and fixed to the drive shaft 8, a swing plate 17 is tiltably connected to the rotary body 15 by a connecting pin 16, and rotation is regulated by a guide rod 18 horizontally suspended in a fixed position. has been done. Further, the left end portions of each of the piston rods 12 are connected to the swing plate 17, and when the rotating body 15 is rotated by the rotation of the drive shaft 8 and the swing plate 17 is tilted, the left end portions of the piston rods 12 are connected to each other through the piston rods 12. piston 11
is designed to move back and forth. Then, as the suction pressure in the suction chamber 4 changes, the piston smee opening changes, the inclination angle of the rocking plate 17 changes, and the compression capacity is controlled.

The configuration described above is similar to that of a conventional variable displacement compressor.

Next, to describe the main part of the present invention, a first valve means 30 is provided in the rear housing 3 that partitions the discharge chamber 5 and the suction chamber 4, and the first valve means 30 is opened and closed. , are provided to control the pressure of the crank chamber 7. That is.

The first valve means 30 includes a suction pressure chamber 31 and a discharge pressure chamber 32.
are provided facing each other, the suction pressure chamber 31 is connected to the suction chamber 4 via the communication path 4a, and the discharge pressure chamber 32 is connected to the air supply path 5.
They are provided so as to communicate with the discharge chamber 5 via a (discharge pressure supply passage). and suction pressure chamber 31
A pressure sensitive chamber 33 communicating with the second valve means 50 mentioned above is provided facing each other, and a diaphragm 34 is provided interposed between both chambers 31 and 33. In addition, a spring 35 is inserted in the pressure sensitive air 33, and the diaphragm 3 is normally
4 is provided so as to be biased in the direction of the discharge pressure chamber 32. On the other hand, the discharge pressure chamber 32 is provided with a valve seat 36 at one end near the suction pressure chamber 31, and a boat 39 is defined through the valve seat 36. Then, an air supply passage 7a for discharge pressure is extended from the same port 39,
The tip thereof is provided so as to face the crank chamber 7. Further, one end of a valve rod 40 is connected to the aforementioned diaphragm 34, and the valve rod 40 extends in the direction of the discharge pressure v32, and its tip end connects to the port 39 and the valve seat 36.
The discharge pressure chamber 32 is provided so as to pass through the discharge pressure chamber 32 . A conical opening/closing valve 37 is fitted into the tip of the valve rod 40 so as to be movable forward and backward in correspondence with the valve seat 36. That is, the Igl leap valve 37 is provided so that it can be opened and closed through the movement of the diaphragm 34. Further, a spring 41 is inserted into the discharge pressure chamber 32 so that its end engages with the on-off valve 37.
The valve seat 36 is biased toward the valve seat 36 (closing direction).

Further, the rear housing 3 is provided with a blow-by gas escape passage 20a that communicates the crank chamber 7 and the suction chamber 4. 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, and this communication passage 50a communicates with atmospheric pressure via a second valve means 50, and a communication passage 50c that extends to the discharge chamber 5. are in communication with each other. The second valve means 50 is for selectively communicating the communication passage 50a from the pressure sensitive chamber 33 with the communication passage 50b communicating with atmospheric pressure or the communication passage 50c from the discharge chamber 5, and is generally used. directional control valve,
An electromagnetic three-way valve etc. can be used.

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

When the compressor is not operating, the second valve means 5
0 opens the communication paths 50a and 50b, and the pressure sensitive chamber 3
3 communicates with atmospheric pressure. In the first valve means 30,
The diaphragm 34 has a pressure difference (pressure in the suction pressure chamber 31>atmospheric pressure + biasing force of the spring 35, hereinafter referred to as "atmospheric pressure + spring 35").
The biasing force J of ``set pressure'') causes the air supply passage 7 to move backward in all 33 pressure-sensitive directions (the valve seat 36 is closed by the on-off valve 37 and the air supply passage 7 connects the discharge pressure chamber 32 and the crank chamber 7).
a is in a closed state). That is, crank 7
is in communication with the suction chamber 4 (maintained at a suction pressure state), 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, the swing plate 17 swings at a large swing angle if the cooling load in the passenger compartment is large, and the screws 1 to 11 are rotated. A large-volume 4-compression operation is performed by reciprocating with a large stroke.

When the passenger compartment is cooled down and the cooling load (evaporator heat load) is reduced by carrying out such a human suspension operation for a certain period of time, the suction pressure of the refrigerant gas sent from the evaporator to the suction chamber 4 decreases. will decrease. Then, in the first valve means 30, this suction pressure is
When the pressure drops below the set pressure J, the diaphragm 34 is pushed toward the suction pressure chamber 31 due to the pressure difference, and the on-off valve 37 is pushed out.
You can get an open state. By opening the on-off valve 37 in this way, the air supply passage 7a connecting the discharge pressure chamber 32 and the crank chamber 7 is opened, and the entire discharge
The discharged gas inside is sent into the crank chamber 7. In this way, the discharge gas is sent into the crank chamber 7, and the pressure in the rank v7 increases, thereby reducing the stroke of each piston 11, that is, the swinging inclination angle of the swinging plate 17. The effect can be obtained by reducing the compression capacity gradually.

The operation described above is similar to that of a conventional variable displacement compressor.

Next, the unique effects of the compressor of this embodiment will be explained.

As described above, in normal compression operation, the second valve means 50 opens the communication passage 50a and the communication passage 50b, and the second valve means 50 opens the communication passage 50a and the communication passage 50b,
The pressure sensitive chamber 33 Lt in the valve means 30 communicates with atmospheric pressure. Here, if it is desired to arbitrarily reduce the compression capacity during acceleration, etc., a voltage signal is sent from the outside via an amplifier to the second valve means 5.
0, the communication path 50a and the communication path 50b are closed, and at the same time, the communication path 50a and the communication path 50c are opened.

As a result, the pressure sensitive chamber 33 of the first valve means 3o and the discharge chamber 5 are communicated with each other, the discharged gas is introduced into the pressure sensitive chamber 33, and the "set pressure" is displaced.

In other words, even if the suction pressure (the pressure inside the suction pressure chamber 3) is constant, as described above, the pressure in the daicephram 34 will increase due to the pressure increase inside the pressure sensitive chamber 33 due to the introduction of the exit gas. The control point is displaced and the daicephram 34 is moved to the suction pressure chamber 3.
You can press in one direction to hear the on/off valve 37.

Therefore, in the variable capacity suspension compressor of this embodiment, the timing and amount of introduction of the discharge gas introduced from the discharge chamber 5 into the crank chamber 7 can be controlled arbitrarily, and as a result, the
The pressure inside the crank chamber 7 can be raised momentarily to perform a low volume bottle compression operation.

(Example 2) In the above-mentioned Example 1, the suction pressure chamber 31 and the pressure sensitive chamber 33
The pressure sensitive chamber 33 is separated from the compressor by a diaphragm 34, and communicates with atmospheric pressure during normal compression operation. Therefore, if the diaphragm 34 becomes loose due to long-term use of the compressor, or if high gas pressure and atmospheric pressure are repeatedly applied to the diaphragm 34 due to repeated switching between the discharge chamber and atmospheric pressure, From there, the suction gas in the suction pressure chamber 31 gradually leaks into the pressure sensitive chamber 33, and as a result, there is a possibility that the suction gas leaks into the atmosphere.

The second embodiment takes this point into consideration, and as shown in FIG. communication path 50
b- and a communication path 50c extending to the discharge chamber 5, respectively.

Further, a spring 35 coupled to the diaphragm 34 is inserted on the suction pressure chamber 31 side, and the diaphragm 34 is always biased toward the pressure sensitive chamber 33. Note that other specific structures are the same as in the first embodiment.

The unique effects of the second embodiment will be explained below.

In the second embodiment, the second valve means 50
' indicates the communication path 50a, the communication path 50b-, and the communication path 50c.
We are closing communication with. That is, the pressure sensitive chamber 33 is in a sealed state, and at this time, the diaphragm 34 retreats in the direction of the pressure sensitive chamber 33 due to the pressure difference (pressure of the suction pressure chamber 31 + biasing force of the spring 35 > pressure of the pressure sensitive chamber 33). state (the valve seat 36 is closed by the on-off valve 37). Then, the engine start i is carried out in a dark manner for a certain period of time,
When the cooling load decreases and the suction pressure decreases, the pressure difference (pressure in the suction pressure chamber 31 + biasing force of the spring 35 (pressure sensitive chamber 3
3 pressure) pushes the diaphragm 34 toward the suction pressure chamber 31, and the on-off valve 37 becomes open, changing to a small capacity operation.

Next, if you want to arbitrarily reduce the compression capacity during acceleration, etc.,
As in the first embodiment, by applying a voltage signal to the second valve means 50 to open the communication passage 50a and the communication passage 50c, the high pressure gas in the discharge chamber 5 is sent into the pressure sensitive chamber 33 and the diaphragm 34 is pushed toward the suction pressure chamber 31 to open the on-off valve 37. Then, when returning to normal compression operation from this state, in the second embodiment, the second valve means 50' temporarily connects the communication passage 50a and the communication passage 50b' to connect the suction chamber 4 and the pressure sensitive chamber 33. After communicating for a certain period of time, the communication between the communication path 50a, the communication path 50b', and the communication path 50c is closed to bring the pressure sensitive chamber 33 into a sealed state. Therefore, during normal compression operation, the pressure within the pressure sensitive chamber 33 is maintained at the suction pressure just before the pressure sensitive chamber 33 becomes sealed.

In this way, in the second embodiment, the pressure sensitive chamber 33 is in any of the following states: a sealed state, a state in which it is in communication with the suction v4, or a state in which it is in communication with the discharge chamber 5. It does not communicate with atmospheric pressure like 1. Therefore, the compression volume can be arbitrarily controlled as in the first embodiment without causing suction gas to leak into the atmosphere.

In addition, in the embodiments 1 and 2, the second valve means 50 (50-) can be pressed by υ1 at will by an external signal,
High pressure gas pressure is applied to the back surface of the diaphragm 34 to displace the pressure point 11111 of the diaphragm. However, as a means for applying a load to the back surface of the diaphragm to displace the pressure control point of the diaphragm, the method of the above embodiment is used. The electromagnetic solenoid or servo motor can be controlled by an external input such as a voltage signal, etc., using the electromagnetic attraction force of an electromagnetic solenoid or the driving force of a servo motor to apply a variable load directly to the back of the diaphragm. It is also possible to do this.

[Effects of the Invention] As described in detail above, the variable displacement compressor of the present invention has a valve control means provided in an air supply passage communicating between a discharge chamber and a crank chamber, through a variable load input means. By making the pressure control point of the pressure sensing means that controls the on-off valve movable, the on-off valve can be controlled arbitrarily. The timing of introduction can be controlled arbitrarily. Therefore, according to the variable capacity compressor of the present invention, arbitrary compression container control such as reducing the compression capacity during acceleration etc. is possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the entirety of a variable displacement compressor according to an embodiment of the present invention. FIG. 2 is a sectional view showing essential parts of a capacity compressor according to another embodiment of the present invention. FIG. 3 is a sectional view showing the entire conventional variable displacement compressor.

Claims (1)

[Scope of Claims] A suction chamber, a discharge chamber, and a crank chamber are provided, and the vibration is controlled in response to changes in suction pressure through a valve control means provided in an air supply passage that communicates the discharge chamber and the crank chamber. In a variable capacity compressor that controls compression capacity by changing the inclination angle of a moving plate, the valve control means includes an on-off valve that opens and closes the air supply passage;
a pressure-sensitive means coupled to the on-off valve to detect the suction pressure and control the on-off valve; and a variable load input that applies a variable load to the pressure-sensitive means to vary the pressure control point of the pressure-sensitive means. A variable capacity compressor comprising means.