JPH0454834B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention adjusts the compression capacity by changing the tilt angle of the wobble plate in response to changes in the cooling load in the vehicle interior. A oscillating swash plate type compressor is installed so that the pressure in the crank chamber can be maintained at a constant pressure, and the piston stroke is changed by changing the suction pressure. The present invention relates to a mechanism for maintaining the pressure in the crank chamber at a constant pressure, that is, a control mechanism for the crank chamber pressure in a oscillating swash plate type compressor provided to change the oscillating inclination angle of the bull plate.

[Conventional technology]

Generally, in a wobble plate type compressor, multiple cylinder bores are arranged in parallel along the circumferential direction, and the pistons inserted into each cylinder bore are connected continuously through the wobble plate. It is provided so that compression action can be obtained by moving it forward and backward. The wobble plate is provided so that its swing angle can be changed in response to changes in the cooling load in the vehicle interior. In other words, when the cooling load inside the vehicle is large, a large compression capacity can be obtained by increasing the swing angle of the wobble plate, and when the cooling load inside the vehicle is small, the wobble plate can be increased. It is provided so that its compression capacity can be reduced by reducing the swinging inclination angle. Conventionally, one method of maintaining the crank chamber pressure at a constant pressure in such a rocking swash plate type compressor is to connect the discharge chamber and the crank chamber with a communication passage, and to interpose an intervening passage in the communication passage. and a control valve is installed.
A method has been proposed in which the crank chamber pressure is controlled to a constant pressure by opening and closing the same control valve through changes in the crank chamber pressure and sending discharge pressure to the crank chamber through the opening and closing of the control valve. ing.

FIG. 3 is a drawing showing the specific structure of the system, in which a fixed relief passage c is provided in communication between the crank chamber a and the suction chamber b, and the fixed relief passage c allows sliding between the cylinder bore d and the piston e. The gap formed in the friction surface is provided so that blow-by gas flowing into the crank chamber can be constantly released into the suction chamber. Further, a discharge pressure supply passage g is provided in communication between the discharge chamber f and the crank chamber a. A control valve h is provided in the supply passage g, and the control valve h is provided so as to be able to be opened and closed through changes in crank chamber pressure. That is, the control valve h has a bellows between it and the crank chamber a.
A crank pressure chamber i communicating with the crank chamber, and an atmospheric pressure chamber j set at a constant pressure are provided, and when the crank chamber pressure exceeds the set pressure, the control valve h is closed, The pressure in the crank chamber a is maintained at a constant pressure by opening the control valve h when the pressure falls below the set pressure and sending the discharge pressure into the crank chamber a.

[Problem that the invention seeks to solve]

However, the above proposal has a problem in that the compression performance decreases due to the large amount of discharge gas sent into the crank chamber from the discharge chamber. That is, in the above proposal, when the cooling load decreases and the crank chamber pressure falls below the set pressure, in order to increase the pressure in the crank chamber to a constant pressure, the air flows out from the fixed relief passage to the suction chamber. Discharge gas that exceeds the amount of gas (fixed relief amount) must be sent into the crank chamber.In other words, in order to maintain the crank chamber pressure at a constant pressure, a large amount of discharge gas is required, and compression is performed to compensate for that amount. This results in a problem that the capacity decreases.

The present invention is an attempt to improve the above-mentioned problems, and its main purpose is to maintain the crank chamber pressure at a constant level without reducing compression performance. There are problems that need to be solved. That is, the present invention solves the above problems by controlling the opening area (throttling amount) of the relief passage connecting the crank chamber and the suction chamber through changes in the crank chamber pressure. The specific means and effects are as follows.

[Means for solving the problem] A relief passage is provided in communication between the crank chamber and the suction chamber, and a control valve is provided interposed in the relief passage.

The control valve is provided with a crank pressure chamber that communicates with the crank chamber, and a set pressure chamber that faces the crank pressure chamber, and the opening area of the on-off valve is adjusted by changing the differential pressure that occurs between the two pressure chambers. Set it up freely. In other words, the opening/closing valve has a small opening area when the crank chamber pressure is lower than the set pressure chamber pressure, in other words, the opening area is set by the differential pressure generated between the two pressure chambers (normal throttle amount). When the pressure in the crank chamber exceeds the set pressure chamber, the crank chamber opens with a large opening area. It is set up so that it can be done.

[Operation] When the compressor is operating at a large capacity, the pressure in the crank chamber of the control valve is lower than the set pressure, so the relief passage is opened with a normal throttle amount. Under the above operating conditions, the small amount of blow-by gas that flows into the crank chamber is released into the suction chamber through the relief passage that opens with the normal throttle amount, thereby maintaining a constant pressure inside the crank chamber. It can be held in

When the inflow of blow-by gas increases during small-capacity operation, or when the suction pressure fluctuates due to a rise in outside temperature, the pressure in the crank chamber is high, and the control valve Due to the differential pressure generated between the pressure chamber and the set pressure chamber, a state is obtained in which the relief passage opens with a larger opening area in addition to the normal throttle amount. Since the relief passage is opened with a large opening area in this manner, the crank chamber pressure can be released to the suction chamber. That is, the pressure inside the crank chamber can be lowered and the pressure inside the crank chamber can be returned to a constant pressure state.

〔Example〕

Specific embodiments of the present invention will be described below with reference to illustrative drawings.

In both FIGS. 1 and 2, 1 indicates a cylinder block, 2 indicates a front housing, and 3 indicates a rear housing. The cylinder block 1 is formed into a cylindrical shape extending in the front-rear direction, and one end on the front side is covered with a front housing 2, while one end on the rear side is covered with a rear housing with a valve plate 4 interposed therebetween. 3 is crowned. The front housing 2 has a bearing portion 5A for a drive shaft 17, which will be described later, in the center thereof.
On the other hand, a suction chamber 6 and a discharge chamber 7 are provided concentrically in the rear housing 3 with an annular partition wall 8 interposed therebetween. That is, the discharge chamber 7 is located at the center, and the suction chamber 6 is located near the outer periphery so as to surround the discharge chamber 7. More specifically, both chambers 6 and 7 are provided so as to communicate with compression chambers 15 of a cylinder bore 14, which will be described later, through an inlet 9 and an outlet 10 opening in the valve plate 4. A suction valve 11 is provided at the suction port 9 so as to open and close during the suction stroke of the piston 16, which will be described later, and a discharge valve 12 is also provided at the discharge port 10 so as to open and close during the compression stroke of the piston 16. It will be done.

Further, at one end of the front side of the cylinder block 1, a bearing portion 5B is provided at the center thereof, facing the bearing portion 5A, and a coaxial bearing portion 5B is provided.
A plurality of cylinder bores 14 are formed around the outer periphery of the cylinder. and each cylinder bore 1
4 has a compression chamber 15 on the rear side and a piston 16.
are fitted so as to be movable back and forth, and each compression chamber 15 is provided so as to selectively communicate with the suction chamber 6 and the discharge chamber 7 via the suction port 9 and the discharge port 10, as described above.

The front housing 2 also has a crank chamber 1 in communication with each cylinder bore 14.
3 is provided in the crank chamber 13, and a drive shaft 17 is provided in the crank chamber 13 between the two bearing portions 5A and 5B.
is suspended horizontally. A lug plate 18 is mounted on one end of the front side of the drive shaft 17 so as to be rotatable together with the drive shaft 17. Therefore, the lug plate 18 is provided with a contact surface 18a for a sleeve 19, which will be described later, at its center, while a contact surface 18b for the drive plate 20 and a support arm 18c for the drive plate 20 are provided at the periphery of the lug plate 18 at an angle of 180 degrees. It is provided with a deviation angle of . A drive plate 20 formed in an annular shape so as to surround the drive shaft 17 is slidably supported on the support arm 18c along the longitudinal direction of the drive shaft 17. More specifically, on the side of the support arm 18c, an elongated hole 22 is formed with a circular arc whose center point is a connecting portion with a wobble plate 21, which will be described later, while on the side of the drive plate 20, a long hole 22 is formed facing the support arm 18c. A guide pin 23 is horizontally suspended at the tip of the bracket 20a that extends from the bracket 20a, and through the engagement between the elongated hole 22 and the guide pin 23, the bracket 20a rotates together with the drive shaft 17 and can swing in the front-rear direction. supported as possible. Further, the aforementioned sleeve 19 is connected to the drive plate 20 and slidably fitted into the drive shaft 17. That is, the sleeve 19 is connected to the drive plate 20 via a pair of left and right connecting pins 24, 24, and is provided so as to be able to slide in the front and rear directions in conjunction with the swinging of the drive plate 20. And the same driveshaft 1
7, the aforementioned wobble plate 21 is swingably supported via a thrust bearing 25 in a state where its rotation is restricted. Similarly to the drive plate 20, the wobble plate 21 is formed in an annular shape so as to surround the drive shaft 17, and the wobble plate 21 and each of the pistons 16 are connected by connecting rods 26. More specifically, the distance between each wobble plate 21 and the piston 16 is such that when the support arm 18c is rotated to a position where it faces each cylinder bore 14, each piston 16 is
is connected so that it is at the top dead center position.

On the other hand, a crank chamber pressure relief passage 2 is provided between the cylinder bore 14 of the cylinder block 1 and communicates between the crank chamber 13 and the suction chamber 6.
7a and 27b are drilled. And the same escape passage 2
A control valve 28 is provided between 7a and 27b, and the opening and closing of the relief passages 27a and 27b is controlled via the control valve 28. That is, the same control valve 2
8, an atmospheric pressure chamber 30 and a crank pressure chamber 31 are disposed facing each other with a diaphragm 29 in between, and a spring 32 is interposed in the atmospheric pressure chamber 30 to urge the diaphragm 29 toward the crank pressure chamber 31. On the other hand, a pair of ports 34a and 34b are formed in the crank pressure chamber 31 with a valve seat 33 in between, and one port 34a is connected to the crank chamber 13 and the other port by the relief passage 27a. port 3 of
4b are respectively provided to communicate with the suction chamber 6 through a relief passage 27b. Further, in addition to the relief passage 27a, another passage, that is, a crank chamber pressure supply passage 35, is provided between the crank pressure chamber 31 and the crank chamber 13. A spring 36 for biasing the diaphragm 29 toward the atmospheric pressure chamber 30 is interposed in the crank pressure chamber 31, and an on-off valve 37 is connected to the diaphragm 29 and is movable forward and backward. Seat 3
It is provided so that it can be brought into contact with 3. That is, the opening area between the on-off valve 37 and the valve seat 33 can be changed by changing the pressure between the crank pressure chamber 31 (crank chamber pressure) and the atmospheric pressure chamber 30 (set pressure). .

Next, its effect will be explained.

When the compressor stops operating, the pressure in the suction chamber 6 (suction pressure) and the pressure in the crank chamber 13 (crank chamber pressure) are the same, and the control valve 28 Since the pressure inside (crank chamber pressure) exceeds the pressure inside the atmospheric pressure chamber 30 (set pressure), the on-off valve 37 has a gap between the set pressure and the crank chamber pressure between the valve seat 33 and the atmospheric pressure chamber 30. Due to the differential pressure generated, the opening area is larger than the normal throttle amount and is in an open state.

When the compressor is stopped in this manner, the operating state of the compressor can be obtained by transmitting the driving force of the engine to the drive shaft 17 through the connection operation of the electromagnetic clutch.
As the compressor starts operating in this way, the air inside the vehicle is cooled, and as the cooling load decreases, the suction pressure of the refrigerant gas sent from the evaporator to the suction chamber 6 gradually decreases. As the suction pressure decreases, the crank chamber pressure also quickly decreases following the decrease in suction pressure, since the opening area of the on-off valve 37 is larger than the normal throttle amount. And that pressure is atmospheric pressure chamber 3
0, the on-off valve 37 of the control valve 28 operates in the closing direction to reduce the opening area formed between the control valve 28 and the valve seat 33.
A state in which the aperture is opened with a normal aperture amount is obtained.
In this way, a state is obtained in which the relief passages 27a and 27b are opened with the normal throttling amount, and when the suction pressure decreases due to high capacity operation for a certain period of time, the inside of the crank chamber 13 remains constant. As the suction pressure decreases, the drive plate 20 and the wobble plate 21
begins to move in the direction of rocking with a small inclination angle, and a state is obtained in which the piston 16 advances and retreats with a small stroke in each compression chamber 15 (small capacity operating state). When the suction pressure increases due to the small capacity operation state, and the pressure in the crank chamber 13 increases and the pressure exceeds the set pressure of the atmospheric pressure chamber 30, the on-off valve 37 of the control valve 28 is moved to the valve seat. 33, the crank chamber 1
The effect of lowering the pressure inside 3 can be obtained. Then, when the pressure inside the crank chamber 13 drops to a pressure lower than the set pressure of the atmospheric pressure chamber 30, the on-off valve 37 in the control valve 28 operates in the closing direction, and the normal throttle amount is restored between the control valve 28 and the valve seat 33. A state is obtained in which the opening is maintained.

When the pressure in the crank chamber 13 is maintained at a constant pressure and the suction chamber pressure increases, the drive plate 20 and wobble plate 21 swing at a large angle of inclination (large capacity operation state) is obtained.

〔Effect of the invention〕

The present invention is constructed as described above, and includes:
As mentioned above, a control valve is provided in the relief passage bored in the cylinder block that communicates between the crank chamber and the suction chamber, and the control valve controls the change in the differential pressure that occurs between the crank chamber pressure and the set pressure. By opening and closing the valve through the valve and by changing its opening area, the amount of restriction of the relief passage can be adjusted, thereby maintaining the pressure in the crank chamber at a constant level without reducing the discharge capacity. It has now become possible to control the pressure.

[Brief explanation of the drawing]

1 and 2 are drawings showing a first embodiment, in which FIG. 1 is a sectional view showing the entire swinging swash plate compressor according to the present invention, and FIG. 2 is a sectional view showing the control valve portion. It is an enlarged sectional view. Further, FIG. 3 is a sectional view showing the entire swinging swash plate type compressor showing a conventional structure. 1... Cylinder block, 2... Front housing, 3... Rear housing, 4... Valve plate, 5A, 5B... Bearing section, 6... Suction chamber, 7... Discharge chamber, 8... Partition wall, 9 ... Suction port, 10 ... Discharge port, 11 ... Suction valve, 12 ... Discharge valve, 13 ... Crank chamber, 1
4...Cylinder bore, 15...Compression chamber, 16...
...Piston, 17...Driveshaft, 18...
... Lug plate, 18a, 18b ... contact surface,
18c...Support arm, 19...Sleeve, 20
...Drive plate, 20a...Bracket,
21...Watsuburu plate, 22...Long hole, 23
... Guide pin, 24 ... Connection pin, 25 ... Thrust bearing, 26 ... Connecting rod, 27a, 2
7b... Relief passage, 28... Control valve, 29... Diaphragm, 30... Atmospheric pressure chamber, 31... Crank pressure chamber, 32... Spring, 3
3... Valve seat, 34a, 34b... Port, 35...
...Supply passage, 36...Spring, 37...Opening/closing valve.

Claims (1)

[Claims] 1. A crank chamber pressure relief passage is provided in communication between the crank chamber and the suction chamber, and a control valve is provided in the relief passage.
The control valve is provided with a crank pressure chamber communicating with the crank chamber and a set pressure chamber having a set pressure opposite to the pressure in the crank pressure chamber, and the flow path of the relief passage is based on the differential pressure between the two pressure chambers. A crank chamber pressure control mechanism in a rocking swash plate compressor that is equipped with an on-off valve that controls area.