JPH0228715B2 - KAHENYORYOGATAYODOITASHIKIATSUSHUKUKI - Google Patents

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. For example, as a rocking plate compressor,
No. 158382 is publicly 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, the blow-by gas pressure, so the pressure in the crank chamber is higher than the suction pressure, which is the low pressure side. When the load is high, 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. When the heat load decreases (medium load state) and the suction pressure decreases, the degree of opening of the pressure control valve decreases as the suction pressure decreases, thereby causing the pressure in the crank chamber to flow out into the suction pressure chamber. Since the amount decreases, 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 despite the low heat load, the suction pressure on the low pressure side will drop too much, the evaporation temperature of the refrigerant will drop, and the evaporator will freeze.

In order to prevent the evaporator from freezing, an anti-freeze valve (hereinafter referred to as A/F valve) is provided. The A/F valves are check valve type piston valves interposed in communication passages that communicate the high-pressure side discharge pressure chamber and the crank chamber. In a non-freezing region where the discharge pressure is equal to or higher than a predetermined set value, the A and F valves do not open and are kept closed. When the discharge pressure drops from this state to a freezing range below a predetermined set value, the A and F valves open and the pressure in the discharge pressure chamber flows into the crank chamber, increasing the pressure in the crank chamber.
Accordingly, the inclination angle of the rocking plate becomes smaller, the stroke of the piston becomes smaller, and the discharge capacity decreases. As the discharge capacity decreases, the amount of refrigerant passing through the evaporator decreases, thereby preventing the evaporator from freezing.

However, when the amount of refrigerant passing through the evaporator decreases in this way, assuming that the amount of heat exchanged by the evaporator remains the same, the temperature on the low pressure side of the evaporator increases. 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 water to leak into the crank chamber through the A and F valves. The introduced pressure in 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 even though the angle of inclination of the rocking plate increases, the pressure in the discharge pressure chamber detours back to the suction pressure chamber via the crank chamber. Because of this, there are problems such as power loss.

(Object of the invention) The present invention was made in view of the above circumstances, and
We provide a variable capacity rocking plate compressor that is equipped with an A/F valve function to prevent the evaporator from freezing, and a pressure control valve that maintains suction pressure at a constant level without causing power loss. The purpose is to

(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 passed through a communication path that communicates the crank chamber and the suction pressure chamber. In the variable capacity wobble plate compressor, the discharge capacity can be varied by changing the inclination angle of the wobble plate by adjusting it with a pressure regulating valve equipped with the wobble plate. a valve body attached to one end of the bellows that expands and contracts in response to the bellows and opens the communication passage when the suction pressure is above a predetermined set value and closes the communication passage when the suction pressure is below the predetermined set value; the first attached to the other end
a movable body, a first spring that is interposed between the first movable body and the valve body and presses the valve body toward the valve closing side; and a first spring that receives discharge pressure on one side and suction pressure on the other side. a second movable body having a pressure receiving part and moving toward and away from the first movable body; a spring seat disposed facing away from the pressure receiving part; and a spring seat interposed between the spring seat and the second movable body. and when the discharge pressure is less than a predetermined value, the valve body is moved to the valve closing side through the second movable body, the first movable body, the first spring, and the bellows in cooperation with the suction pressure against the discharge pressure. The configuration includes a second spring that presses the

(Function) When the discharge pressure falls below a predetermined value and the evaporator enters the freezing region, the second spring presses the valve body more strongly in the valve closing direction, increasing the valve closing pressure. The pressure in the crank chamber is increased, the inclination angle of the rocking plate is made smaller, the discharge capacity is reduced, and the amount of refrigerant passing through the evaporator is reduced, thereby preventing the evaporator from freezing.

(Example) Hereinafter, one example of the present invention will be described based on the drawings.

FIG. 1 is a cross-sectional view of a variable displacement rocking plate compressor according to the present invention. In the figure, 1 is a housing of the compressor, and the housing 1 includes a cylinder block 2 and one end surface of the cylinder block 2 (see FIG. It consists of a rear head 4 airtightly attached to the left end surface of the cylinder block 2 via a valve plate 3, and a front head 5 airtightly attached to the other end surface (right end surface in the figure) of the cylinder block 2. Inside the housing 1, a crank chamber 6 is defined by the end surface of the cylinder block 2 on the side of the front head 5, and the inner peripheral surface and inner end surface of the front head 5.
The cylinder block 2 is provided with predetermined intervals in the circumferential direction around the drive shaft 7, which is disposed approximately on the center line of the housing 1, and whose axis is parallel to that of the drive shaft 7. A plurality of cylinders 8 are provided, and a piston 9 is slidably fitted into each cylinder 8.

A discharge port 4a through which compressed refrigerant gas is discharged is provided in one end surface (left end surface in the figure) of the rear head 4. A discharge pressure chamber 10 is formed approximately at the center inside the rear head 4, and the discharge pressure chamber 10 is partitioned into a first chamber 10 ₁ and a second chamber 10 ₂ by a partition 11. Drilled aperture hole 1
The first chamber 10 ₁ and the second chamber 10 ₂ communicate with each other through 1a. Therefore, the discharge port 3a is communicated with the discharge port 4a through the first chamber 10 ₁ , the throttle hole 11a and the second chamber 10 ₂ in this order. The discharge port 3a is opened and closed by a discharge valve 12, and the discharge valve 12 is attached to the rear head 4 side of the valve plate 3 with a set screw 14 together with a discharge valve stop 13. It is screwed into the screw hole 2a of the cylinder block 2 through the hole 3c of the plate 3 in an airtight manner. A suction pressure chamber 15 is provided on the outer peripheral side of the discharge pressure chamber 10.
The suction pressure chamber 15 is communicated with the cylinder 8 through a suction port 3b formed in the valve plate 3. The suction port 3b
is opened and closed by the suction valve 16, and the suction valve 1
6 is the cylinder block 2 of the valve plate 3.
attached to the side.

The suction pressure chamber 15 is connected to an outlet of an evaporator of an air conditioner (not shown) via an inlet (not shown), and the discharge pressure chamber 10 is connected to an inlet of a condenser (not shown) via the outlet 4a.

A storage chamber 16 is formed between the cylinder block 2, the valve plate 3, and the rear head 4, and the storage chamber 16 communicates with the crank chamber 6 through a communication passage 2b bored in the cylinder block 2. There is. Further, the storage chamber 16 communicates with the suction pressure chamber 15 through a hole 3d formed in the valve plate 3. The storage chamber 16
A pressure regulating valve 17, which is a main part of the present invention, is housed inside. The pressure regulating valve 17 is for regulating the pressure within the crank chamber 6, and has a cylindrical case 18 as shown in FIG. Case 18
One end surface (the right end surface in the figure) is closed, and the other end surface (the left end surface in the figure) is open. One end surface of the case 18 is brought into contact with the inner end surface of the portion 16a of the cylinder block 2 of the storage chamber 16 via a seat member 19, and the other end surface is brought into contact with the inner end surface of the portion 16b of the valve plate 3 of the storage chamber 16. It is inserted into the storage chamber 16 while keeping it airtight with a ring 20, and is stored in the storage chamber 16 in a state where it is in contact with the inner end surface of the portion 16c of the rear head 4 of the storage chamber 16. A gap exists between the circumferential side of the case 18 and the inner surface of the portion 16a of the cylinder block 2 of the storage chamber 16.

The outer circumferential surface on one end side of the case 18 is a tapered surface 18a whose diameter gradually decreases toward the one end side,
A plurality of holes 18b are bored in the tapered surface 18a at intervals in the circumferential direction. Further, a valve hole 18c is bored in the center of one end surface of the case 18 and communicates with the communication passage 2b of the cylinder block 2.
The communication path 2 of the cylinder block 2 via 9a
It is connected to b. Furthermore, the opening surface of the other end of the case 18 is communicated with the second chamber 10 ₂ of the discharge pressure chamber 10 via a communication passage 21 formed in the rear head 4 . A low-pressure operating section 22 is housed inside the case 18 on one end side of the substantially middle portion in the axial direction, and a high-pressure operating section 23 is housed inside the other end side. The low pressure operating section 22 includes a bellows 24, a valve body 25 attached to one end of the bellows 24 (the right end in the figure), and a first movable body 26 attached to the other end of the bellows 24 (the left end in the figure). and a first spring 27 that presses the valve body 25 toward the valve closing side. The bellows 24 has a hollow cylindrical shape with both end faces open and the circumferential side surface shaped like a bellows.
It can be expanded and contracted in the axial direction according to Ps. The valve body 25 opens and closes the communication passage 2b, and is composed of a valve body 28 and a holding member 29. The valve body 28 has a tapered outer circumferential surface whose diameter gradually decreases toward one end (left end in the figure), and a fitting protrusion 30 is integrally protruded from the center of the other end. When the suction pressure Ps is above a predetermined set value (suction pressure Ps>spring force of the first spring 27), the bellows 24 contracts and the valve body 25 opens, and when the suction pressure Ps is below the predetermined set value. (Suction pressure Ps<1st
(spring force of the spring 27), the bellows 24 expands and the valve body 25 closes. The holding member 29 is located at one end (left end in the figure) of a hollow cylindrical body 31 with both end faces open.
A circular collar 32 is integrally provided on the outer peripheral surface.
Then, the fitting protrusion 3 is placed inside the hollow cylindrical body 31.
0 is fitted and fixed to the valve body 28 and the holding member 29.
The valve body 25 is constructed by integrating the two together. This valve body 25 is connected to the case 18.
The valve body 28 is fitted into the interior of the valve body 28 so as to be slidable in the axial direction, and the one end surface side of the valve body 28 is fitted into the case 18.
The communication passage 2 of the cylinder block 2 is slidably connected to the valve hole 18c of the cylinder block 2 and the hole 19a of the seat member 19.
b Extends inward to open and close the communication path 2b. The first movable body 26 is formed by a circular flange 34 integrally protruding from the outer peripheral surface of the other end of a hollow cylindrical body 33 having one end surface (left end surface in the figure) open and the other end surface closed. Then, the first movable body 26
is fitted into the case 18 substantially in the middle thereof so as to be slidable in the axial direction thereof, and is spaced apart from the valve body 25 . The bellows 24 is located between the facing surfaces of the flange 32 of the valve body 25 and the flange 34 of the first movable body 26.
is interposed, and both ends of the bellows 24 are connected to the flange 3.
2 and 34, respectively, in an airtight manner. The first spring 27 has a coil shape, and one end thereof is connected to the hollow cylindrical body 31 of the valve body 25, and the other end thereof is connected to the hollow cylindrical body 33 of the first movable body 26.
are loosely fitted into the flange 32, 3, respectively, and both end faces are fitted with the flange 32
4, respectively. Therefore, the valve body 25 and the first movable body 26 are pressed in opposite directions by the first spring 27. In addition,
A partition wall 35 that divides the inside into two is fixed to the substantially middle inside of the case 18, and the partition wall 35
This restricts the limit position of movement of the first movable body 26 toward the other end (left end in the figure). Further, the opening pressure of the valve body 25 is determined by the fixed position of the partition wall 35. Note that the space defined by the bellows 24, the valve body 25, and the first movable body 26 is a vacuum, and 70% of the volume of the space is
% to 80% of oil (not shown) is sealed, and the viscosity of the oil in the bellows portion of the first bellows 24 provides a so-called damper effect that softens the expansion and contraction movement of the first bellows 24 when the first bellows 24 is suddenly opened or closed. It is now possible to do so.

The high-pressure operating section 23 connects the second movable body 37, the movable spring seat 38, and the second movable body 37 to the first movable body 37.
It consists of a second spring 39 that presses against the movable body 26 side. The second movable body 37 has a pressing body 40 and a pressure receiving part 4.
Consists of 1. The pressing body 40 has a hollow cylindrical shape with both end faces open, and one end face thereof (the right end face in the figure).
The side of the partition wall 35 is slidably moved into and out of contact with the first movable body 26 through the center hole 35a of the partition wall 35. The pressure receiving part 41 receives the discharge pressure Pd on one side (the right side in the figure) and the suction part Ps on the other side (the left side in the figure), and has a disk shape with a fitting hole 43 in the center. ing. And the pressing body 40
The other end of the pressing body 4 is fitted and fixed into the fitting hole 43.
The second movable body 37 is configured by integrating the pressure receiving portion 41 and the pressure receiving portion 41 into one body. This second
The movable body 37 is fitted into the middle of the case 18 so as to be slidable in the axial direction of the case 18, and is attached to the partition wall 35.
The first movable body 26 is opposed to the first movable body 26 via.
The movable spring seat 38 has a disk shape, is fitted inside the other end of the case 18 so as to be slidable in the axial direction thereof, and is spaced apart from the second movable body 37 . The second spring 39 has a coil shape, and one end surface thereof is in contact with the center portion of the second pressure receiving portion 41 of the second movable body 37, and the other end surface is in contact with the center portion of the movable spring seat 38. There is. Therefore, the second movable body 37 and the movable spring seat 38 are connected to the second spring 3
9 is pressed in the relative direction. A cylindrical member 44 having one end face (right end face in the figure) open and the other end face (left end face in the figure) closed is fitted and fixed inside the other end side of the partition wall 35 of the case 18 . One end surface is in contact with the partition wall 35, and an adjustment screw 46 is screwed into the center of the closing wall 45 on the other end surface, and the inner end surface of the adjustment screw 46 is in contact with the movable spring seat 3.
It is in contact with the center of 8. Therefore, the limit position of movement of the movable spring seat 38 to the left side in the drawing (towards the side opposite to the valve body 25) is regulated by the adjustment screw 46, and the setting force of the second spring 39 is adjusted by the adjustment screw 46. can do. The cylindrical member 4
The inside of the second pressure receiving part 4 communicates with the inside of the case 18 on the one end side from the approximately middle part through the core hole 40a of the pressing body 40, so that the suction pressure Ps is transferred to the second pressure receiving part 4
It is designed to act on other aspects of 1. In addition,
A notch 40b is provided on one end surface of the pressing body 40, and the notch 40b allows the center hole 40a and the case 18 to be roughly connected even when the one end surface of the pressing body 40 is in contact with the first movable body 26. Communication between the middle portion and the interior of one end side is ensured. Said second movable body 3
7. The interior of one end of the cylindrical member 44 in which the movable spring seat 38 and the spring 39 are located has a hole 47 bored along the axial direction in the circumferential wall of the cylindrical member 44 and a connection between the rear head 4 and the rear head 4. It communicates with the second chamber 10 ₂ of the discharge pressure chamber 10 via a passage 21 .

The case 18 is pressed to the right side in the drawing (towards the seat member 9) by a wavy spring 17a, and as a result, the contact surface portion 2c between the seat member 19 and the cylinder block 2 and the contact surface portion between the seat member 19 and the case 18 18d are kept airtight, so that refrigerant gas does not leak from the crank chamber pressure Pw side of these contact surfaces 2c and 18d to the suction pressure Ps side.

The pressure regulating valve 17 is configured as described above.

The drive shaft 7 has a bearing 49 at its end on the rear head 4 side in the center hole 48 of the cylinder block 2.
The front head 5 side end thereof is rotatably supported in the center hole 50 of the front head 5 via a bearing 51. The end of the drive shaft 7 on the front head 5 side is located in a protruding cylindrical portion at the center of the outer end surface of the front head 5, and a clutch (not shown) and a pulley (not shown) are provided at the end of the drive shaft 7 on the front head 5 side. is connected. The pulley is an in-vehicle engine (not shown)
is connected to the output shaft side pulley of the engine by a drive belt (not shown), and the rotation of the engine is connected to the output shaft side pulley of the drive shaft 7.
transmitted to.

A rotation holding member 53 that transmits the rotation of the drive shaft 7 to the swing plate mounting member 52 is fitted on the outer peripheral surface of the drive shaft 7 on the front head 5 side. and is supported by the front head 5. The lower portions of the opposing surfaces of the rotation holding member 53 and the rocking plate mounting member 52 are rotatably coupled via a link arm 55. That is, one end of the link arm 55 is connected to the rotation holding member 5 by the pin 56.
The pin 5 is rotatably attached to the lower part of one side of 3, and the other end is attached to the pin 5.
7, they are each rotatably coupled to the lower side of one side of the swing plate mounting member 52.

The center hole 52a of the rocking plate mounting member 52 is loosely fitted around the outer periphery of the drive shaft 7, and a hinge ball is fitted around the outer periphery of the approximately intermediate portion of the drive shaft 7 so as to be slidable in the axial direction. It is in sliding contact with the outer periphery of 58. The hinge ball 58 and the rotation holding member 53
A corrugated spring 59 is provided on the outer periphery of the drive shaft 7 between the
A spring 59 urges the hinge ball 58 toward the cylinder block 2 (to the left in the figure). Further, a stopper 60 is provided to protrude from the drive shaft 7 on the cylinder block 2 side by the hinge ball 58, and the stopper 60
0 and the drive shaft 7 between the hinge ball 58
A plurality of leaf springs 61 and coil springs 62 are provided on the outer periphery.
These springs 61 and 62 bias the hinge ball 58 toward the front head 5 (to the right in the figure).

A radial bearing 6 is attached to the swing plate mounting member 52.
3. Swing plate 66 via thrust bearings 64 and 65
are rotatably provided, and these thrust bearings 6
4 and 65 are fixed to the swing plate mounting member 52 by a bearing holding plate 67. The swing plate 66
The tip 66a facing the piston 9 and the piston 9 are rotatably connected by a piston rod 68 having balls 68a and 68b at both ends, respectively.
The piston rod 68 reciprocates in the axial direction within the cylinder 8 as the piston rod 68 swings, thereby sucking and compressing refrigerant gas.

One restrant pin 69 is provided on the swing plate 66 from near the center to the outer end thereof,
A plate-shaped slipper 70 is rotatably provided on the outer periphery of the restrant pin 69 near its outer end.

On the inner circumferential surface of the housing 1 facing the slipper 70, there is a groove extending from the end surface of the cylinder block 2 on the side of the front head 5 to the inner circumferential surface of the front head 5 and parallel to the axial direction of the drive shaft 7. Two guide plates 71 are provided, and the restrant pin 69 and slipper 70 move along grooves formed between the two guide plates 71. Therefore, the swing plate 66 is restrained from moving in the circumferential direction of the drive shaft 7 by the guide plate 71, and swings about the hinge ball 58 in a direction parallel to the axial direction of the drive shaft 7. They are starting to move.

Next, the operation of the variable capacity rocking plate compressor of the present invention having the above configuration will be explained.

When the rotational power of an on-vehicle engine (not shown) is transmitted to the drive shaft 7 via a drive belt, pulley, clutch, etc. (not shown) in order, the drive shaft 7 rotates together with the rotation holding member 53 and the swing plate mounting member 52.
As the rocking plate 66 rotates, the pressure inside the crank chamber 6 increases.
According to Pw, the hinge ball 58 swings in a direction parallel to the axis of the drive shaft 7 as a fulcrum, and the inclination angle changes, and as the inclination angle changes, the stroke motion given to the piston 9 changes, resulting in a discharge capacity. changes. That is, as the pressure Pw in the crank chamber 6 decreases, the inclination angle of the rocking plate 66 increases, and accordingly, the stroke momentum of the piston 9 also increases, and the discharge capacity increases. Conversely, as the pressure Pw in the crank chamber 6 increases, the inclination angle of the rocking plate 66 decreases, and accordingly, the stroke momentum of the piston 9 also decreases, resulting in a decrease in discharge capacity.

However, under high load conditions (discharge pressure Pd and suction pressure
Ps is above a predetermined set value), the second chamber of the discharge pressure chamber 10 acts on one side of the pressure receiving part 41 of the second movable body 37 via the communication passage 21 of the rear head 4 and the hole 47 of the cylindrical member 44. Discharge pressure Pd within 10 ₂
However, the hole 3d of the valve plate 3, the portion 16a of the cylinder block 2 of the storage chamber 16, the hole 18b of the tapered surface 18a of the case 18, the inside of the case 18 on one end side from the approximately middle part, the notch 40b of the pressing body 40,
The suction pressure Ps in the suction pressure chamber 15 acting on the other side of the pressure receiving part 41 and the second spring 3 through the center hole 40a
9 (Pd>Ps+spring force of the second spring 39), the second movable body 37 resists the pressing force due to the resultant force of the second spring 39 and the suction pressure Ps. The left side in the figure (the side opposite to the first movable body 26)
The pressing body 40 of the second movable body 37 is moved away from the first movable body 26 . Further, the suction pressure Ps in the suction pressure chamber 15 is applied to the hole 3d of the valve plate 3, the portion 16a of the cylinder block 2 of the storage chamber 16, and the tapered surface 1 of the case 18.
By acting on the bellows 24 through the hole 18b of 8a, the valve body 25 is pushed against the pressing force of the first spring 27 and moved to the left side in the figure (the second movable body 37 side), that is, to the valve opening side. Then, the valve body 25 is in a state where the communication passage 2b of the cylinder block 2 is fully opened. In such a state, the pressure Pw inside the crank chamber 6 is lowered to the communication passage 2b of the cylinder block 2 and the seat member
9 hole 19a, valve port 18 on one end surface of case 18
c. By escaping into the suction pressure chamber 15 at the maximum flow rate through the hole 18b of the tapered surface 18a, the portion 16a of the cylinder block 2 of the storage chamber 16, and the hole 3d of the valve plate 3 in order, the crank The pressure Pw inside the chamber 6 drops significantly. Therefore,
The inclination angle of the rocking plate 66 becomes the maximum, and accordingly, the stroke amount of the piston 9 also becomes the maximum, and the discharge amount increases to the maximum.

Next, in a medium load state (state where the discharge pressure Pb and suction pressure Ps are at predetermined values), the discharge pressure Pd overcomes the pressing force due to the resultant force of the second spring 39 and the suction pressure Ps, so the second movable The body 37 is in a state where it is pressed to the left side in the figure (the side opposite to the first movable body 26),
No pressing force is applied to the first movable body 26.

In addition, the valve body 25 is moved by the first spring 2 due to the suction pressure Ps.
The valve body 25 is pushed toward the valve closing side against the pressure force of 7, and the valve body 25 is in a state where the communication passage 2b is partially narrowed to the opening position.

Therefore, the pressure Pw in the crank chamber 6 is reduced, and the pressure Pw in the crank chamber 6 increases.
As the rocking plate 66 rises, the inclination angle of the rocking plate 66 becomes approximately intermediate between the maximum inclination angle and the minimum inclination angle, and accordingly, the stroke amount of the piston 9 also becomes an intermediate state, and the discharge capacity becomes an intermediate state.

Furthermore, in a low load state (state where the discharge pressure Pd and suction pressure Ps are below the predetermined set value), the suction pressure Ps
The valve body 25 is pressed toward the valve closing side. Furthermore, the second movable body 37 is pushed to the right in the figure (toward the first movable body 26 side) by the pressing force due to the resultant force of the second spring 39 and the suction pressure Ps against the discharge pressure Pd. The entire low-pressure actuating part 22, that is, the bellows 24, the valve body 25, the first movable body 26, and the first spring 27, is pressed and moved toward the valve closing side by the pressing body 40, and the valve body 2
5 narrows down the opening amount of the communicating path 2b. This reduces the amount of pressure Pw in the crank chamber 6 that escapes from the communication path 2b to the suction pressure chamber 15 side.
The pressure Pw in the crank chamber 6 further increases, and accordingly, the inclination angle of the rocking plate 66 becomes smaller, the stroke amount of the piston 9 also becomes smaller, and the discharge capacity decreases. As a result, the control characteristics of the compressor of the present invention become as shown in FIG. In FIG. 3, the vertical axis is the suction pressure Ps, and the horizontal axis is the discharge pressure Pd (instead of the discharge pressure Pd, a value representing a heat load such as the outside air temperature may be used). The shaded area in Fig. 3 indicates the frozen area of the evaporator, but the discharge pressure
The lower the Pd, the more the second spring 39 and the suction pressure
The valve body 25 is pressed toward the valve closing side by the pressing force resulting from the combined force with Ps, thereby more strongly closing the communication passage 2b and reducing the discharge capacity. In other words, reducing the discharge capacity means reducing the flow rate of refrigerant to the evaporator, which increases the outlet temperature of the evaporator, which increases the outlet pressure of the evaporator and increases the outlet temperature, which prevents the evaporator from freezing. Freezing of the evaporator can be reliably prevented without entering the area.

Although the internal space of the bellows 24 is evacuated and filled with oil to obtain a damper effect, the invention is not limited to this, and the internal space of the bellows 24 may be opened to the atmosphere, or an inert It may also be filled with gas.

As described in detail above, the variable displacement wobble plate compressor of the present invention adjusts the pressure in the crank chamber in which the wobble plate is accommodated by a pressure regulating valve interposed in a communication path that communicates the crank chamber and the suction pressure chamber. In the variable displacement wobble plate compressor configured to be able to vary the discharge capacity by changing the inclination angle of the wobble plate, the pressure regulating valve is a bellows that expands and contracts according to the suction pressure. a valve body attached to one end of the bellows to open the communication passage when the suction pressure is above a predetermined set value and close the communication passage when the suction pressure is below a predetermined set value; and a valve body attached to the other end of the bellows. a first movable body; a first spring that is interposed between the first movable body and the valve body and presses the valve body toward the valve closing side; and a first spring that applies discharge pressure to one side and suction pressure to the other side. a second movable body, each having a receiving pressure portion and moving toward and away from the first movable body; a spring seat disposed facing away from the pressure receiving portion; and between the spring seat and the second movable body. and when the discharge pressure is below a predetermined value, the second
It is characterized by comprising a movable body, a first movable body, a first spring, and a second spring that presses the valve body toward the valve closing side via the bellows.

Therefore, it is possible to prevent the evaporator from freezing by providing the A/F valve function, and the suction pressure can be maintained constant by the pressure regulating valve, yet there is an effect that power loss does not occur.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a cross-sectional view of a variable displacement wobble plate compressor, FIG. 2 is an enlarged cross-sectional view of the circular portion of FIG. 1, and FIG. It is a control characteristic diagram of the machine. 2b...Communication path, 6...Crank chamber, 15...
Suction pressure chamber, 17...pressure adjustment valve, 24...bellows, 25...valve body, 26...first movable body, 27...
...Second spring, 37...Second movable body, 38...Movable spring seat (spring seat), 39...Second spring, 41...
Pressure receiving part, 66... rocking plate.

Claims (1)

[Claims] 1. By adjusting the pressure in the crank chamber in which the rocking plate is housed with a pressure regulating valve installed in a communication passage that communicates the crank chamber and the suction pressure chamber, and changing the inclination angle of the rocking plate, In a variable capacity rocking plate compressor configured to be able to vary the discharge capacity, the pressure regulating valve is attached to one end of a bellows that expands and contracts according to suction pressure, and when the suction pressure is equal to or higher than a predetermined set value, the pressure regulating valve a valve body that opens the passage and closes the communication passage when the suction pressure is below a predetermined set value; and a first valve body that is attached to the other end of the bellows.
a movable body, a first spring that is interposed between the first movable body and the valve body and presses the valve body toward the valve closing side; and a first spring that receives discharge pressure on one side and suction pressure on the other side. a second movable body having a pressure receiving part and moving toward and away from the first movable body; a spring seat disposed facing away from the pressure receiving part; and an interposition between the spring seat and the second movable body. and when the discharge pressure is below a predetermined value, the second
A variable capacity rocking plate compressor comprising a movable body, a first movable body, a first spring, and a second spring that presses the valve body toward the valve closing side via a bellows.