JPS62191673A - Variable delivery compressor with swing plate - Google Patents

Abstract

PURPOSE:To provide possibility of holding the suction pressure constant using a pressure control valve and prevent power loss and self-exciting vibration of delivery valve by changing the inclination angle of a swing plate through pressure adjustment inside the crank chamber, and thereby making the delivery capacity of compressor variable. CONSTITUTION:In this compressor in which the delivery capacity is made vari able by changing the inclination angle of a swing plate accommodated in a crank chamber 7 through adjustment of the pressure therein, a pressure control valve 26 consisting of a bellows valve is interposed in No. 1 passage 28 which puts a suction pressure chamber 27 defined between cylinder head 4 and valve plate 3 in communication to the crank chamber 7. The two chambers 27, 7 are also in communication through No. 2 passage 30, while a No. 3 passage 31 puts the crank chamber 7 in communication with a discharge pressure cham ber 32, wherein opening and closing of No. 1-3 passages 28, 30, 31 are con trolled by a sole selector valve 35 according to the pressure in said delivery pressure chamber 32. No. 2 passage 30 is equipped with an orifice 33 as a throt tle mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a variable displacement wobble plate compressor used for compressing refrigerant gas in a vehicle air conditioner.

(Prior art and its problems) Conventionally, a variable displacement type is configured such that the discharge volume can be varied by adjusting the pressure in the crank chamber in which the rocking plate is housed and changing the inclination angle of the rocking plate. As a rocking plate compressor, for example, Japanese Patent Laid-Open No. 158382/1982 is known.

In this type of compressor, the pressure in the crank chamber is created by the pressure leaking between the cylinder and the piston, that is, blow pie gas pressure.

The pressure inside the crank chamber is higher than the suction pressure, which is the low pressure side. When the normal load condition occurs, that is, when the suction pressure exceeds a predetermined set value, the pressure control valve installed in the communication passage between the crank chamber and the suction pressure chamber opens, and the pressure inside the crank chamber (blow-by gas ) flows into the suction pressure chamber, the pressure in the crank chamber decreases, and as a result, the inclination angle of the rocking plate increases, the stroke of the piston increases, and the discharge capacity increases. As the discharge capacity increases, the suction pressure decreases, and as the suction pressure decreases, the 1/11 valve degree of the pressure control valve decreases, causing the pressure in the crank chamber to flow out into the suction pressure chamber. As a result, the pressure in the crank chamber increases, and as a result, the inclination angle of the rocking plate decreases, the stroke of the piston decreases, and the discharge capacity decreases. This operation changes the discharge capacity.

On the other hand, in a low load state, if a constant amount of refrigerant continues to flow even though the heat load is low, the discharge pressure on the high pressure side will drop too much and the evaporator will freeze.

In order to prevent the evaporator from freezing, an anti-freeze valve (hereinafter referred to as an A-F valve) is provided. The Δ·I7 valve is a check valve type piston valve installed in a communication passage that communicates the high pressure side discharge pressure chamber with the crank chamber. In the non-freezing region where the discharge pressure is above a predetermined set value, A-[? The valve is not opened but is maintained in a closed state. When the discharge pressure drops from this state to a freezing range below a predetermined set value, the A-F valve opens and the pressure inside the discharge pressure chamber flows into the crank chamber, increasing the pressure inside the crank chamber. The inclination angle of the rocking plate becomes smaller, the stroke of the screw 1 becomes smaller, and the discharge capacity 1 decreases.As the discharge capacity decreases, the amount of refrigerant passing through the evaporator decreases, so the evaporator Freezing is prevented.

However, when the amount of refrigerant passing through the evaporator decreases in this way, the temperature on the low pressure side of the evaporator increases, assuming that the amount of heat exchanged by the evaporator remains the same. When the temperature of a refrigerant increases, its pressure increases, and if an attempt is made to increase the pressure and reduce the discharge capacity, the low pressure side (suction pressure) will also increase. Then, the bellows of the pressure control valve, which is installed to keep the suction pressure on the low pressure side constant, operates and opens the valve body, causing the intake pressure to be introduced into the crank chamber via the A-F valve. The pressure inside the discharge pressure chamber returns to the suction pressure chamber via the pressure control valve. As a result, the pressure in the crank chamber decreases, and the inclination angle of the rocking plate increases, causing the pressure in the discharge pressure chamber to flow through the crank chamber to the suction pressure chamber even though it is operating at full stroke. Since it returns in a detour state, there are problems such as power loss and self-excited vibration of the discharge valve and suction valve, which generates noise.

(Object of the Invention) The present invention has been made in view of the above circumstances, and is equipped with an A/F valve function to prevent the evaporator from freezing, and a pressure control valve to maintain a constant suction pressure. It is an object of the present invention to provide a variable displacement oscillating plate compressor that does not cause power loss or self-excited vibration of a discharge valve.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, the pressure in the crank chamber in which the rocking plate is accommodated is adjusted to change the inclination angle of the rocking plate. , in a variable capacity wobble plate compressor configured to be able to vary the discharge capacity, a mutually independent first chamber communicating with a rank chamber and a suction pressure chamber is provided.
a passageway, a second passageway, a third passageway communicating the crank chamber and the discharge pressure chamber, and a third passageway which is interposed in the first passageway and closes when the pressure in the suction pressure chamber is below a predetermined setting value and is set to a predetermined setting value. a pressure control valve that opens when the pressure in the discharge pressure chamber becomes equal to or higher than a predetermined set value to communicate the crank chamber and the suction pressure chamber via the first passage; Closing: Switching to open the second and third passages at the same time as ζ, and to open the first passage and close the second and third passages at the same time when the pressure in the discharge pressure chamber becomes equal to or higher than the predetermined set value. a valve interposed in the second passageway and configured to
The present invention is equipped with a throttle mechanism that narrows the passage so that the cross-sectional area of the passage becomes smaller than the cross-sectional area of the third passage.

(When the discharge pressure drops below a predetermined value (during low load), the switching valve shuts off the 15th passage that communicates between the suction pressure chamber and the crank chamber, and the discharge pressure The amount of pressure inside the main crank chamber flowing into the suction pressure chamber through the second passage is smaller than the amount flowing into the crank chamber through the third passage, so that the pressure in the crank chamber is maintained at a certain level and the angle of inclination of the rocking plate is increased. It operates while maintaining the

(Example) An example of the present invention will be described below based on the drawings. In the figure, reference numeral 1 denotes a housing, which is composed of a cylindrical case 2 and a head member 5 that is fluid-tightly attached to one end surface (the left end surface in the figure) of the case 2 via a valve plate 3. A cylinder block 6 is integrally formed inside the case 2, and a crank chamber 7 is defined by an end surface of the cylinder block 6 on the head member 5 side, an inner circumferential wall of the case 2, and an inner surface of the head member 5. ing. An oil reservoir 8 is formed inside the lower part of the case 2, and the oil reservoir 8 communicates with the crank chamber 7. The cylinder block 6 is provided with a predetermined interval in the circumferential direction around a drive shaft 9 disposed substantially along the central axis of the housing 1 and with the axis parallel to that of the drive shaft 9. A plurality of cylinders 10 are arranged, and a piston 11 is provided in each cylinder 10.
are fitted in a slidable manner. The drive shaft 9 has its cylinder head 4 side end rotatably supported in the center hole 6a of the cylinder block 6 via a ball bearing 12, and its head member 5 side end supported by an arm member 13.
The head member 5 is rotatably supported on the inner circumferential surface of the head member 5 via a large-diameter ball bearing 14 and a large-diameter ball bearing 14 in this order. The shaft end of the head member 5 side end of the drive 9 extends through the center hole 5a of the head member 5 and extends outward, and the boot 5 is fitted into the extended end. has been done. A mechanical seal 16 is interposed between the boss portion 13a of the arm member 13 and the center hole 5a of the head member 5, and the space between the boss portion 13a and the center hole 5a of the head member 5 is maintained airtight. ing. The pulley 15 is a drive belt (not shown) attached to a pulley on the output shaft side of an on-vehicle engine (not shown).
The rotation of the engine is transmitted to the drive shaft 9. A sleeve-shaped slider 17 is fitted on the outer periphery of the approximately intermediate portion of the drive shaft 9 in the axial direction so as to be able to slide on the drive shaft 9 in the axial direction but not to rotate in the circumferential direction. 17 is adapted to rotate together with the drive shaft 9. A center hole 18a of a disc-shaped swing plate 18 is loosely fitted into the outer periphery of the slider 17 at an approximately intermediate portion in the axial direction, and both sides are rotatably connected to the slider 17 via l-runion pins 19. has been done. A cam at the tip of the arm portion 13b of the arm member 13 is provided at a portion between the parallel guide portions 20 that protrude in the radial direction at a predetermined position on the surface of the swing plate 18 facing the head member 5. Surface 13c is engaged. A coil spring 23 is provided between a pin 21 protruding from both sides of the arm portion 13b of the arm member 13 and a pin 22 protruding from the parallel guide portion 20 of the swing plate 18.
are each set up. The tip of a piston rod 24 protruding from the piston 1 is attached to a ball joint 25 on the surface of the swing plate 18 on the cylinder block 6 side.
are connected to each other via. Therefore, the rocking plate 1
As the piston 8 rotates, the piston 11 slides. Further, the angle of inclination of the swing plate 18 relative to the vertical plane changes depending on the pressure within the crank chamber 7, and the stroke of the piston 11 increases or decreases due to the change in the angle of inclination.

The pressure inside the crank chamber 7 is controlled by a pressure control valve 26. The pressure control valve 26 is a bellows valve having a valve body 26b provided at the tip of a bellows 26a, and is provided in the cylinder block 6 as shown in FIG. 4. That is, the pressure control valve 26 is interposed in a first passage 28 that communicates the crank chamber 7 with a suction pressure chamber 27 on the low pressure side defined between the cylinder head 4 and the valve plate 3. has been done. The first passage 28 is formed across the cylinder block 6 and the valve plate 3, communicates the valve chamber 28a with the crank chamber 7, and is opened and closed by the valve body 26b. 1 communication hole 28b, the valve chamber 28a and the suction pressure chamber 2.
7, and a second communication hole 28c communicating with 7. A bellows 26a of the pressure control valve 26 is accommodated in the valve chamber 28a, and as the bellows 26El expands and contracts, the valve body 26b
The first communicating hole 28b is opened and closed. The bellows 26a expands and contracts by sensing the suction pressure, and when the suction pressure is below a predetermined set value, the valve body 26b expands to keep the first communication hole 28b in a closed state. When the suction pressure exceeds the set value, the bellows 26
a resists its own biasing force so that the valve body 26b
The communication hole 28b is reduced so as to be kept open. The pressure control valve 26 has a valve pressure adjustment mechanism 29 in which the opening pressure can be adjusted by operating from the outside of the cylinder head 4. A second passage 30 and a third passage 31 are parallel to the second communication hole 28c of the first passage 28.
is provided. These second and third passages 30 and 3
1 is formed across the cylinder block 6 and the valve plate 3. The second passage 30 communicates the suction pressure chamber 27 and the crank chamber 7, and is independent from the first passage 28. The third passage 31 communicates with a discharge pressure chamber 32 on the high pressure side defined between the cylinder head 4 and the valve plate 3. An orifice (throttling mechanism) 33 is provided inside the end of the second passage 30 on the crank chamber 7 side, and the orifice 33
, the cross-sectional area of the second passage 30 is smaller than the cross-sectional area of the third passage.

A valve fitting chamber 34 is provided in the cylinder block 6 so as to cross the second communication hole 28c of the first passage 28, the second passage 30, and the third passage 31, respectively. The valve fitting chamber 34 is perpendicular to the second communication hole 28c of the first passage 28, the second passage 30, and the third passage 31, and a switching valve 35 is slidable inside the valve fitting chamber 34. is fitted in.

The switching valve 35 is a spool valve, and has three land portions 35a, 35b, 35c and two annular grooves 35d, 35.
It has e. One end surface of the switching valve 35 serves as a pressure receiving surface, and the one end surface has a stepped portion 3 on one end surface of the one-valve fitting chamber 34.
6, and the working pressure chamber 37 communicates with the inside of the discharge pressure chamber 32 via a communication passage 38 and a third passage 31. When the discharge pressure in the discharge pressure chamber 32 is in a state equal to or higher than a predetermined setting value (normal load state), the switching valve 35 is operated by the first counteractuation pressure chamber 37 due to the discharge pressure.
As shown in FIG. 4, the switching valve 35 is moved to the first switching position as shown in FIG. The annular groove 35a allows the first passage 28 to
The second communication hole 28c is in an open position. Furthermore, when the discharge pressure in the discharge pressure chamber 32 is below a predetermined set value (low load state), the switching valve 35 is pushed toward the operating pressure chamber 37 by the biasing force of a spring 39, which will be described later. As shown in FIG.
8c is closed, the annular groove 35 of the switching valve 3S
The second and third passages 3o and 3]- are in a position to be opened by cl and 35e. The switching valve 35 is urged to the first switching position by a coiled spring 39, and the spring 39 is interposed between the other end surface of the valve fitting chamber 34 and the other end surface of the switching valve 35. . The movement limit position of the switching valve 35 toward the working pressure chamber 37 is restricted by one end surface of the switching valve 35 coming into contact with the step portion 36 .

In addition, 40 in FIGS. 1 and 2 is an oil pump, one end of which communicates with the suction port 40a and an oil passage 41 provided in the cylinder block 6, the other end of which is open into the crank chamber 7, A base end of an oil guide tube 42 is connected to the open end, and the tip of the oil guide tube 42 is immersed in the oil in the oil reservoir 8 and opened. Further, a discharge port 40b of the oil pump 40 is connected to an oil guide passage 43 inside the cylinder block 6, so that lubricating oil is supplied to each sliding portion. Note that the slider 17
The cylinder head 4 is moved by the coil spring 44.
Pressed to the side.

Next, the operation of the variable capacity rocking plate compressor of the present invention having the above configuration will be explained. When rotational power is transmitted from an on-vehicle engine (not shown) to the drive shaft 9 via the belt and pulley 15, the drive shaft 9 rotates together with the arm member 13 integrated therewith, and the arm member 13 has its arm portion 13b. The swing plate 18 engaged with the tip is rotated. The angle of inclination of the rocking plate 18 changes depending on the pressure within the crank chamber 7, and as the angle of inclination changes, the stroke motion given to the piston 11 changes, thereby changing the displacement. That is, as the pressure in the crank chamber 7 decreases, the inclination angle of the rocking plate 18 increases, and accordingly, the stroke momentum of the piston 11 also increases, and the discharge capacity increases. Conversely, as the pressure within the crank chamber 7 increases, the inclination angle of the rocking plate 18 decreases, and accordingly, the stroke momentum of the screw 1 hem 11 also decreases, resulting in a decrease in discharge capacity.

Therefore, in a normal load state (state 71 where the discharge pressure is higher than a predetermined set value), the switching valve 35 is activated by the spring 39 due to the discharge pressure.
4, and in this state, if the pressure in the suction pressure chamber 27 is below a predetermined set value, the pressure control valve 26 is closed as shown in FIG. The valve is used to close the first communication hole 28b of the first passage 28, so that the pressure inside the crank chamber 7 does not flow out to the low pressure side, and the pressure inside the crank chamber 7 increases. Rocking plate 18
Since the inclination angle of is decreased, the discharge capacity is decreased.

When the pressure in the suction pressure chamber 27 increases with the decrease in the discharge volume and exceeds a predetermined set value, the bellows 26a of the pressure control valve 26 contracts in response to the pressure in the suction pressure chamber 27 to reduce the pressure. The control valve 26 is opened and the first communication hole 2 of the first passage 28 is opened.
Open 8b. Therefore, the pressure inside the crank chamber 7 is
Because it flows out into the suction pressure chamber 27 through the first communication hole 28b, the valve chamber 28a, and the second communication hole 28c of the passage 28,
The pressure inside the crank chamber 7 decreases, and accordingly the rocking plate 1
Since the inclination angle of 8 increases, the discharge capacity increases. In order to maintain the pressure in the suction pressure chamber 27 at a preset constant value, the pressure control valve 26 opens and closes in response to changes in the pressure in the suction pressure chamber 27, thereby controlling the pressure in the crank chamber 7. changes and 1. Accordingly, the inclination angle of the rocking plate 18 changes, and the discharge capacity changes.

On the other hand, in a low load state (a state in which the discharge pressure is below a predetermined set value), the switching valve 35 is in the second switching position as shown in FIG. 5 due to the biasing force of the spring 39 against the discharge pressure. In this state, the second communication hole 28c of the first passage 28 is closed by the land portion 35a of the switching valve 35. Therefore, even if the pressure control valve 26 opens, the second
Since the communication hole 28c is closed, the pressure in the crank chamber 7 does not flow out into the suction pressure chamber 27 from the first passage 28. Further, in the second switching position of the switching valve 35, the pressure in the discharge pressure chamber 32 is transferred to the crank chamber 7 via the third passage 31.
As the refrigerant flows into the evaporator, the pressure in the crank chamber 7 increases, and the angle of inclination of the rocking plate 18 decreases, reducing the discharge capacity, which reduces the amount of refrigerant passing through the evaporator. Freezing is prevented. In this case, the pressure within the crank chamber 7 flows out into the suction pressure chamber 27 via the second passage 30 having the orifice 33;
Since the amount of discharge pressure flowing into the crank chamber 7 via the third passage 31 is greater than the amount of outflow, the inside of the crank chamber 7 is maintained at a certain pressure. Note that the throttle mechanism 33 is not limited to the fixed orifice shown in the above embodiment, but may also be a variable metering valve whose opening degree changes depending on the pressure in the crank chamber 7, a variable opening check valve, or the like. It may be configured as follows.

(Effects of the Invention) As detailed above, the variable displacement rocking plate compressor of the present invention is capable of changing the inclination angle of the rocking plate by adjusting the pressure inside the crank chamber in which the rocking plate is housed. , a variable capacity wobble plate compressor configured to be able to vary the discharge capacity, comprising a first passage and a second passage which are independent of each other and which communicate the crank chamber and the suction pressure chamber; and the crank chamber and the discharge pressure chamber. A third passage is interposed in the first passage and is closed when the pressure in the suction pressure chamber is below a predetermined set value, and opens when the pressure in the suction pressure chamber is equal to or higher than the predetermined set value. a pressure control valve that communicates the crank chamber and the suction pressure chamber; and a pressure control valve that closes the first passage when the pressure in the discharge pressure chamber becomes equal to or less than a predetermined set value, and simultaneously opens the second and third passages. a switching valve that opens the first passage and simultaneously closes the second and third passages when the pressure in the discharge pressure chamber becomes equal to or higher than the predetermined set value; The present invention is equipped with a throttle mechanism that throttles the two passages so that the cross-sectional area thereof becomes smaller than the cross-sectional area of the third passage.

Therefore, it is equipped with an anti-freeze valve function to prevent the evaporator from freezing, and while the pressure control valve can maintain a constant suction pressure, it does not cause power loss or self-excited vibration of the discharge valve and suction valve. This effect is achieved.

4. Drawing 171 flf! ,! The explanatory drawings show one embodiment of the present invention, in which FIG. 1 is a partially cutaway side view of a variable capacity wobbling plate compressor of the present invention, and FIG. 2 is a cross-sectional view of the same;
FIG. 3 is a view taken along the line Ill-1rl in FIG. 2, and FIGS. 4 and 5 are enlarged sectional views of essential parts for explaining the operation.

7... Crank chamber, 1-8... Rocking plate, 26...
Pressure control valve, 27... suction pressure chamber, 28 first passage;
30: Second passage, 31: Third passage, 33: Orifice (throttle mechanism), 35: Switching valve.

Claims (1)

[Claims] 1. In a variable displacement wobble plate compressor configured to be able to vary the discharge capacity by adjusting the pressure in the crank chamber in which the wobble plate is housed and changing the inclination angle of the wobble plate, the above-mentioned a first passage and a second passage which are independent of each other and which communicate the crank chamber and the suction pressure chamber; a third passage which communicates the crank chamber and the discharge pressure chamber; and a third passage which is interposed in the first passage and which is connected to the suction pressure chamber. a pressure control valve that closes when the pressure of the engine is below a predetermined set value and opens when the pressure of When the pressure in the discharge pressure chamber becomes equal to or less than the predetermined set value, the first passage is closed, and at the same time the second and third passages are opened, and when the pressure in the discharge pressure chamber becomes equal to or higher than the predetermined set value, the first passage is opened. At the same time said second and third
A variable capacity variable capacity characterized by comprising a switching valve that closes a passage, and a throttle mechanism that is interposed in the second passage and throttles the second passage so that the cross-sectional area of the second passage becomes smaller than the cross-sectional area of the third passage. Type rocking plate compressor.