JP3412263B2 - Refrigeration circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration circuit suitable mainly for vehicle air conditioning.

[0002]

2. Description of the Related Art A general swash plate compressor is disclosed in Japanese Patent Laid-Open No. 62-87680. In this compressor, a suction chamber, a discharge chamber, and a crank chamber are formed in a housing and a bore is formed, a piston is reciprocally housed in the bore, and a compression chamber is formed by the end surface of the piston and the bore. Has been done. A drive shaft is rotatably supported on the housing, and a rotor is supported on the drive shaft so as to be synchronously rotatable in the crank chamber. In the crank chamber, a rotary swash plate is moored to the rotor via a hinge mechanism so as to be synchronously rotatable and tiltable, and a swing swash plate is moored to the rotary swash plate while being prevented from rotating. The swing swash plate is moored by the piston and the rod in the crank chamber. Further, the housing is provided with a bleed passage that connects the crank chamber and the suction chamber, and a capacity control valve that adjusts the pressure in the crank chamber by detecting the suction pressure.

As shown in FIG. 8, the compressor 80 is
When used for vehicle air-conditioning, it is usually equipped with an electromagnetic clutch, and as a minimum, condenser 81, expansion valve 84 and evaporator 85.
Together with this, it constitutes a general refrigeration circuit. That is, the condenser 81 is connected to the discharge chamber of the compressor 80, and the condenser 81
An expansion valve 84 is connected to the expansion valve 84, and an evaporator 85 is connected to the expansion valve 84.
And the evaporator 85 is again connected to the suction chamber of the compressor 80. A liquid receiver 82 may be connected between the condenser 81 and the expansion valve 84, and the expansion valve 84 is controlled by a temperature sensitive tube 84a provided between the evaporator 85 and the compressor 80. Sometimes.

In this refrigeration circuit, the rotation of the engine as a drive source is transmitted to the drive shaft of the compressor 80 via an electromagnetic clutch. In the compressor 80, the rotation of the drive shaft causes the rotary swash plate to rotate at a predetermined tilt angle, and only the swing motion of the rotary swash plate is transmitted to the swing swash plate. Therefore, the oscillating movement of the swash plate causes the piston to reciprocate in the bore via the rod, thereby compressing the refrigerant in the suction chamber in the compression chamber and then discharging the refrigerant to the discharge chamber.

The high temperature and high pressure refrigerant discharged from the discharge chamber is condensed and liquefied by the condenser 81, and the liquefied refrigerant is decompressed by the expansion valve 84 to be a low temperature and low pressure mist. The atomized refrigerant is evaporated by the evaporator 85. At this time, since the surrounding air is cooled by the heat of vaporization, the passenger compartment and the like are cooled. After this, the refrigerant is the compressor 8
It is inhaled again into the suction chamber of 0.

In the meantime, in the compressor 80, when the suction pressure Ps falls below the set pressure as the heat load decreases, the capacity control valve starts the supply of the refrigerant at the discharge pressure Pd into the crank chamber, whereby the extraction passage is opened. Regardless of the derivation of the refrigerant from the crank chamber to the suction chamber due to, the pressure Pc in the crank chamber is increased, so the discharge capacity by the compression chamber is reduced. On the contrary, in the compressor 80, the suction pressure P increases as the heat load increases.
When s rises above the set pressure, the capacity control valve stops the supply of the refrigerant having the discharge pressure Pd into the crank chamber,
Since the pressure Pc in the crank chamber is lowered by drawing the refrigerant from the crank chamber to the suction chamber through the bleed passage, the discharge capacity of the compression chamber is increased.

Thus, in the compressor, the discharge capacity changes according to the change in heat load.

[0008]

However, in a general refrigeration circuit, since the discharge capacity of the compressor 80 is adjusted only by the capacity control valve, when the heat load is large, the compressor is operated by high-speed operation of the engine, for example. If the drive shaft of 80 is rotated at a high speed, the compressor 80 may generate noise or impair durability.

That is, in the compressor, the drive shaft is driven at a rotational speed that can vary depending on the operating condition of the engine. Therefore, as shown in FIG. 9, the relationship between the heat load and the discharge capacity is the rotational speed of the drive shaft ( N). At this time, in the state where the drive shaft of the compressor 80 is rotated at a normal speed by the normal operation of the engine, the suction pressure Ps detected by the displacement control valve of the compressor 80 is increased if the heat load is large. Therefore, the pressure Pc in the crank chamber decreases due to the closing of the capacity control valve, and the compressor 80 tries to operate at the maximum inclination angle of the rotary swash plate and the swing swash plate, that is, the maximum discharge capacity.

However, if the drive shaft of the compressor 80 is rotated at high speed due to the high speed operation of the engine, the compression chamber sucks the refrigerant in the suction chamber in a short time. For this reason,
The suction pressure Ps in the suction chamber of the compressor 80, and further in the pipeline leading to the evaporator 85, is reduced. In this case, the suction pressure Ps detected by the displacement control valve of the compressor 80 becomes low, so the pressure Pc in the crank chamber is opened by opening the displacement control valve.
Becomes higher, the compressor 80 tends to be operated with a reduced discharge capacity, that is, the rotation swash plate and the swing swash plate have a reduced inclination angle.

On the other hand, since the piston tries to reciprocate in the bore in a short time, it tries to extend the stroke by inertial force, and in the compressor 80, the rotary swash plate and the swing swash plate increase the inclination angle, that is, the discharge capacity. Is increased. Thus, in the compressor 80 in the normal operation state, the time (T) and the discharge capacity show the relationship of the curve A in FIG. 10, while the drive shaft is rotated at a high speed when the heat load is large. Then, the relationship of the curve B of FIG. 10 is shown. That is, in the upper right region of FIG. 9 where the inertial force of the piston increases, the discharge capacity of the compressor is periodically changed and the compressor becomes unstable. At this time,
In the compressor 80, the rotation swash plate, the swing swash plate, and the like change the tilt angle, and the hinge mechanism and the like repeat sliding contact. For this reason, the compressor 80 may generate noise and lose durability due to wear of the hinge mechanism and metal fatigue.

According to the present invention, in the refrigeration circuit, even if the drive shaft of the compressor is rotated at a high speed when the heat load is large, noise of the compressor can be prevented and high durability can be maintained. It is an issue to be solved.

[0013]

In order to solve the above-mentioned problems, a refrigeration circuit according to a first aspect of the present invention includes a drive shaft driven by a drive source at a variable rotation speed and a bore formed in a cylinder block. A piston that reciprocates, compresses the refrigerant sucked from the suction chamber and discharges it to the discharge chamber, and a tilt angle that rotates with the drive shaft in the crank chamber and reduces the stroke of the piston based on the pressure increase in the crank chamber. A compressor having a displaceable swash plate element and a bleed passage that connects the crank chamber and the suction chamber is provided, and the refrigerant discharged from the compressor is passed through a condenser, an expansion valve, and an evaporator. In the refrigeration circuit that circulates in a circulating manner, a regulating valve is provided between the discharge chamber and the condenser to increase the pressure in the crank chamber when the upstream / downstream pressure difference becomes larger than a set pressure. To

In order to solve the above-mentioned problems, a refrigeration circuit according to a second aspect of the present invention reciprocates in a bore formed in a cylinder block and a drive shaft which is driven by a drive source at a variable rotational speed to reciprocate the suction chamber. A piston that compresses the refrigerant sucked from the refrigerant and discharges it into the discharge chamber, and a swash plate element that rotates together with the drive shaft in the crank chamber and that reduces the stroke of the piston based on the pressure increase in the crank chamber. And a refrigeration circuit that includes a compressor including an extraction passage that connects the crank chamber and the suction chamber, and circulates the refrigerant sent from the compressor through a condenser, an expansion valve, and an evaporator. A regulating valve is provided between the evaporator and the suction chamber to increase the pressure in the crank chamber when the upstream / downstream pressure difference becomes larger than a set pressure.

A refrigeration circuit according to a third aspect of the present invention is the refrigeration circuit according to the first or second aspect, wherein the adjusting valve is configured to introduce the discharged refrigerant into the crank chamber when the pressure difference between the upstream and downstream sides becomes larger than the set pressure. It is characterized by being. A refrigeration circuit according to a fourth aspect is the refrigeration circuit according to the first or second aspect, wherein the adjusting valve is configured to reduce the opening degree of the extraction passage when the pressure difference between the upstream and the downstream becomes larger than the set pressure. It is characterized by

The refrigerating circuit according to claim 5 is the refrigerating circuit according to claim 1,
In the refrigeration circuit described in 2, 3, or 4, the compressor is characterized by being provided with a displacement control valve for adjusting the pressure in the crank chamber by detecting the suction pressure. The refrigeration circuit according to claim 6 is the refrigeration circuit according to claim 1, 2, 3, 4 or 5.
In the refrigeration circuit described above, the drive shaft of the compressor is directly connected to the drive source by a drive pulley.

The refrigeration circuit according to claim 7 is the refrigeration circuit according to claim 1.
In the refrigeration circuit described in 2, 3, 4, 5 or 6, the adjusting valve is built in the compressor.

[0018]

In the refrigeration circuit according to the first aspect of the present invention, the regulating valve is provided between the discharge chamber of the compressor and the condenser. Here, when the drive shaft of the compressor is rotated at a high speed when the heat load is large, the flow rate of the refrigerant is large between the discharge chamber of the compressor and the condenser, and The pressure difference exceeds the set pressure.

Therefore, the adjusting valve increases the pressure in the crank chamber. Here, in the refrigeration circuit according to the third aspect, the regulating valve introduces the refrigerant in the discharge chamber into the crank chamber to increase the pressure in the crank chamber. In the refrigeration circuit according to claim 4,
The adjusting valve reduces the opening of the bleed passage and increases the pressure in the crank chamber. Thus, in the compressor, the swash plate element reduces the tilt angle, the stroke of the piston is reduced, and the discharge capacity is reduced.

Here, in the refrigeration circuit according to the fifth aspect, since the compressor is provided with the capacity control valve, the capacity control valve can increase the pressure in the crank chamber by decreasing the suction pressure. At this time, the regulating valve increases the pressure in the crank chamber independently of the capacity control valve. That is, claim 3
In the refrigeration circuit described, the regulating valve introduces the refrigerant in the discharge chamber into the crank chamber through a passage independent of the capacity control valve.
Therefore, even if the capacity control valve is closed, the adjustment valve reliably increases the pressure in the crank chamber. Even when the capacity control valve is open, the adjusting valve introduces a larger amount of refrigerant into the crank chamber than when the capacity control valve alone is used to increase the pressure in the crank chamber, and the pressure in the crank chamber is controlled only by the capacity control valve. More surely than when raising with.

Further, in the refrigeration circuit according to the fourth aspect, the regulating valve reduces the opening degree of the extraction passage. Therefore, regardless of whether the capacity control valve is closed or opened, the adjustment valve further increases the pressure in the crank chamber compared with the case where only the capacity control valve is used.
In this way, the reliably increased pressure in the crank chamber counters the inertial force of the piston, and the discharge capacity is reliably reduced.

As a result, in the compressor, the discharge capacity is not changed periodically if the drive shaft is rotated at a high speed when the heat load is large. In the refrigeration circuit according to the second aspect, the adjusting valve is provided between the evaporator and the suction chamber of the compressor. Here, if the drive shaft of the compressor is rotated at a high speed when the heat load is large, the flow rate of the refrigerant is large even between the evaporator and the suction chamber of the compressor, and The pressure difference of is larger than the set pressure. Therefore, similarly to the above, the regulating valve surely raises the pressure in the crank chamber, and the compressor has a discharge capacity as long as the drive shaft of the compressor is rotated at high speed when the heat load is large. It is not changed periodically.

In the refrigeration circuit according to the sixth aspect, since the drive shaft of the compressor is directly connected to the drive source by the drive pulley,
The drive shaft will be driven as long as the drive source is operating. At this time, in this refrigeration circuit, if the drive shaft of the compressor is rotated at high speed when the heat load is large, the discharge capacity of the compressor is reliably reduced by the adjusting valve according to claims 1 to 5. Therefore, excessive cooling or the like is prevented.
Further, in this way, since the conventional electromagnetic clutch can be omitted, it is possible to prevent deterioration of, for example, the driving feeling of the vehicle when the electromagnetic clutch is connected or disconnected, and to reduce weight, reduce power consumption, improve fuel efficiency, and the like. .

In the refrigeration circuit according to the seventh aspect of the present invention, since the adjusting valve is built in the compressor, it is not necessary to secure a space for the adjusting valve in, for example, the vehicle or to separately prepare a mounting member. In addition, when the heat load is not so large or the drive shaft of the compressor is not rotating at a high speed, it is between the discharge chamber of the compressor and the condenser or the suction of the evaporator and the compressor. Since the flow rate of the refrigerant is not so large between the chamber and the chamber, the pressure difference between the upstream and the downstream becomes smaller than the set pressure. Therefore, at this time, the pressure adjustment in the crank chamber by the adjustment valve is hardly or completely performed.

It is also conceivable to provide a regulating valve between the condenser and the expansion valve or between the expansion valve and the evaporator, but between the condenser and the expansion valve or between the expansion valve and the evaporator. Since the refrigerant is liquid, it is considered difficult for the adjusting valve to detect the pressure difference between the upstream and the downstream due to the flow rate of the refrigerant.

[0026]

Embodiments 1 to 6 embodying the invention described in each claim will be described below with reference to the drawings. (Embodiment 1) The refrigerating circuit of the embodiment 1 is defined by claims 1, 3, 5,
7 is embodied.

This refrigeration circuit is used for air conditioning of a vehicle, and as shown in FIG. 1, a compressor 50 equipped with an electromagnetic clutch 40 and a capacity control valve 18 and a discharge chamber 15 of the compressor 50 are provided with pipes. A condenser 51 connected by a path 50a,
Liquid receiver 5 connected to this condenser 51 by a conduit 50b
2, the expansion valve 53 connected to the liquid receiver 52 by a pipe 50c, the expansion valve 53 connected by a pipe 50d, and the downstream side is connected again to the suction chamber 16 of the compressor 50 by a pipe 50e. Evaporator 54, evaporator 54 and compressor 5
A temperature-sensing cylinder 53 that is provided between the temperature-sensing cylinder 53 and the expansion valve 53 and controls the expansion valve 53.
a.

In the compressor 50, the front housing 2 is joined to the front end side of the cylinder block 1, and the rear plate 3 and the like are sandwiched between the rear housing 3 and the rear end side of the cylinder block 1.
Are joined. In the crank chamber 5 formed by the front housing 2 and the cylinder block 1, a drive shaft 6 having one end extended from the front housing 2 and fixed to the armature of the electromagnetic clutch 40 is accommodated.
The drive shaft 6 is rotatably supported by a shaft sealing device and a radial bearing provided between the front housing 2 and the cylinder block 1. A thrust bearing and a leaf spring are interposed between the other end of the drive shaft 6 and the valve plate 4, etc. A plurality of bores 1a are formed in the cylinder block 1 at positions surrounding the drive shaft 6, and pistons 7 are housed in the bores 1a, respectively.

In the crank chamber 5, a rotor 8 is fixed to the drive shaft 6 between the drive shaft 6 and the front housing 2 via a thrust bearing so that the rotor 8 can rotate synchronously with the drive shaft 6. The rotary swash plate 10 is moored so as to be rotatable in synchronization with the rotor 8. Further, a sleeve 11 is slidably provided on the peripheral surface of the drive shaft 6 in the crank chamber 5, and a rotary swash plate 10 is swingably moored to a pivot shaft 11a protruding from the sleeve 11. . A swing swash plate 12 is moored to the rotary swash plate 10 via a thrust bearing or the like, and the swing swash plate 12 has a rotation stopper groove 2a of the front housing 2 which is slidable only in the axial direction. The stop pin 12a is fixed. A rod 14 is anchored between the swing swash plate 12 and each piston 7, so that each piston 7 can reciprocate in each bore 1a according to the tilt angle of the swing swash plate 12. .

The pressing spring 1 is provided between the sleeve 11 and the circlip fixed to the drive shaft 6 on the cylinder block 1 side.
Equipped with 3. The pressing spring 13 allows the rotary swash plate 10 to come into contact with the rotor 8, so that the swing swash plate 12 is maintained at the maximum tilt angle at the time of starting. Further, the swing swash plate 12 can be maintained at the minimum tilt angle in the state where the pressing spring 13 is contracted most.

In the rear housing 3, a discharge chamber 15 is formed on the center side, and a suction chamber 16 is formed outside the discharge chamber 15. The end face of each piston 7 is each bore 1
The discharge chamber 15 and each compression chamber formed between the valve plate 4 and
The discharge ports 15a formed in the above are communicated with each other, and each discharge port 15a can be opened and closed by a discharge valve (not shown) whose opening is regulated by a retainer 15b on the discharge chamber 15 side. Further, each compression chamber and the suction chamber 16 are communicated with each other by each suction port 16a formed in the valve plate 4, and each suction port 16a can be opened and closed by a suction valve (not shown) on each compression chamber side. .

Further, the rear housing 3, the valve plate 4, the cylinder block 1 and the like are provided with a bleed passage 17a for communicating the crank chamber 5 and the suction chamber 16, and
Air supply passage 17b that connects the discharge chamber 15 and the crank chamber 5 to each other.
And the air supply passage 1 is formed in the rear housing 3.
A capacity control valve 18 is provided in the middle of 7b. The capacity control valve 18 is provided with a detection passage 18 a that communicates with the suction chamber 16.
Thus, the diaphragm 18b can be displaced up and down, and the displacement of the diaphragm 18b allows the ball 18c to adjust the opening of the air supply passage 17b.

The characteristic structure of the compressor 50 is the adjusting valve 30 described below. That is, the rear housing 3 is formed with an adjustment chamber 20 that communicates with the discharge chamber 15 through the opening 19. The adjusting chamber 20 is formed in a columnar space, and a supply air adjusting passage 21 communicating with the supply air passage 17b is provided through the bottom surface on the opening 19 side. The valve body 22 is housed in the adjusting chamber 20 on the side of the air supply adjusting passage 21.
Is urged toward the air supply adjusting passage 21 by a pressing spring 23. The valve body 22 is formed such that the tip on the air supply adjustment passage 21 side has a thin V-shaped cross section, and the adjustment chamber 2 is formed on the inclined surface on the tip side.
A diaphragm 22a is formed to connect 0 and the conduit 50a. Thus, between the discharge chamber 15 and the condenser 51,
An adjustment valve 30 that can adjust the opening degree of the air supply adjustment passage 21 by the valve body 22 is provided.

The condenser 51, the liquid receiver 52, the expansion valve 53, the evaporator 54, the temperature sensing cylinder 53a and the respective pipelines 50a to 50e are commercially available ones. In the refrigeration circuit configured as described above, the rotation of the engine (not shown) as a drive source is transmitted to the drive shaft 6 of the compressor 50 by the electromagnetic clutch 40. In the compressor 50, the rotation of the drive shaft 6 causes the rotary swash plate 10 to rotate at a predetermined tilt angle in synchronization with the rotor 8, and only the swing motion of the rotary swash plate 10 is transmitted to the swing swash plate 12. To be done. Therefore, the piston 7 reciprocates in the cylinder 1 a via the rod 14 by the rocking motion of the rocking swash plate 12. As a result, the refrigerant in the suction chamber 16 is compressed in the compression chamber and then discharged into the discharge chamber 15. The refrigerant discharged into the discharge chamber 15 has the opening 19, the adjustment chamber 20, and the throttle 22.
It is discharged to the condenser 51 through the conduit 50a via a.

The high-temperature and high-pressure refrigerant is condensed and liquefied by the condenser 51, and the liquefied refrigerant is held in the liquid receiver 52 by the pipe 50b in a constant amount. Liquid receiver 52 to conduit 50
The refrigerant supplied to the expansion valve 53 by c is the temperature sensing cylinder 53a.
Under the control of, the pressure is reduced by the expansion valve 53 to form a low temperature / low pressure mist. Then, the atomized refrigerant is piped 50d.
Is supplied to the evaporator 54 and is evaporated by the evaporator 54. At this time, since the surrounding air is cooled by the heat of vaporization, the vehicle interior is cooled. After this, the refrigerant is sucked again into the suction chamber 16 of the compressor 50 through the conduit 50e.

In the meantime, in the compressor 50, when the suction pressure Ps in the suction chamber 16 decreases as the heat load decreases, the diaphragm 18b of the capacity control valve 18 is displaced with its upper surface as an arc, and the ball 18c is formed. The air supply passage 17b is opened. Therefore, the supply of the refrigerant having the discharge pressure Pd in the discharge chamber 15 into the crank chamber 5 starts, and the pressure Pc in the crank chamber 5 increases. Therefore, the back pressure acting on the piston 7 is increased, the inclination angles of the rotary swash plate 10 and the swing swash plate 12 are reduced, the stroke of the piston 7 is reduced, and the discharge capacity is reduced.

On the contrary, in the compressor 50, when the suction pressure Ps in the suction chamber 16 rises as the heat load increases, the diaphragm 18b of the capacity control valve 18 is displaced with its lower surface as an arc, and the ball 18c. Closes the air supply passage 17b. Therefore, the supply of the refrigerant having the discharge pressure Pd in the discharge chamber 15 into the crank chamber 5 is stopped, and the pressure Pc in the crank chamber 5 is lowered. Therefore, the back pressure acting on the piston 7 is reduced, the tilt angles of the rotary swash plate 10 and the swing swash plate 12 are increased, the stroke of the piston 7 is increased, and the discharge capacity is increased.

Here, when the drive shaft 6 of the compressor 50 is rotated at a high speed by the high speed operation of the engine when the heat load is large, the valve body 22 in the adjusting chamber 20 of the adjusting valve 30 is supplied. Due to the large flow rate of the refrigerant and the presence of the throttle 22a, a pressure difference larger than the set pressure occurs between the air adjustment passage 21 side and the pipeline 50a side. That is, the pipe 50a side of the valve body 22 has a low discharge pressure Pd (L), and the supply air adjustment passage 21 side of the valve body 22 has a high discharge pressure Pd.
d (H).

Therefore, the valve body 22 of the adjusting valve 30 overcomes the pressing spring 23 to open the air supply adjusting passage 21. As a result, the refrigerant in the discharge chamber 15 is supplied to the crank chamber 5 through the adjustment chamber 20 and the air supply adjustment passage 21 and the air supply passage 17b in the capacity control valve 18. Therefore, the pressure Pc in the crank chamber 5 is increased and the discharge capacity of the compressor 50 is reduced.

At this time, the compressor 50 has a capacity control valve 18
Is provided, the capacity control valve 18 controls the suction pressure Ps.
It is possible to increase the pressure Pc in the crank chamber 5 by decreasing At this time, the adjusting valve 30 is the capacity control valve 18
Independently of, the pressure Pc in the crank chamber 5 is increased. That is, the adjusting valve 18 introduces the refrigerant in the discharge chamber 15 into the crank chamber 5 through the air supply adjusting passage 21 independent of the capacity control valve 18. Therefore, even if the capacity control valve 18 is closed, the adjusting valve 30 surely increases the pressure Pc in the crank chamber 5. Further, even if the capacity control valve 18 is open, the adjustment valve 30 has only the capacity control valve 18 and the pressure P in the crank chamber 5 is reduced.
A larger amount of refrigerant is introduced into the crank chamber 5 than when increasing c, and the pressure Pc in the crank chamber 5 is increased more reliably than when increasing the capacity control valve 18 alone.

In this way, the further increased pressure Pc in the crank chamber 5 opposes the inertial force of the piston 7, and the discharge capacity is reliably reduced. On the other hand, when the heat load is not so large or the drive shaft 6 of the compressor 50 is not rotated at a high speed, the flow rate of the refrigerant is small and the valve body 22 in the adjusting chamber 20 of the adjusting valve 30 is small. A pressure difference smaller than the set pressure does not occur between the air supply adjustment passage 21 side and the pipeline 50a side. Therefore, the valve body 2 of the adjusting valve 30
2 defeats the pressing spring 23 to close the air supply adjusting passage 21. In this way, the adjusting valve 30 causes the pressure Pc in the crank chamber 5 to rise.
However, the normal capacity control by the capacity control valve 18 is performed as described above.

Thus, in the compressor, the rotational speed (N) of the drive shaft and the discharge capacity have the relationship shown in FIG. That is, in the compressor 50, when the drive shaft 6 is rotated at a high speed when the heat load is large, the discharge capacity is reliably reduced, and therefore the discharge capacity is not changed periodically. . Therefore, in the compressor 50, the rotary swash plate 10 and the swing swash plate 1
2, the sleeve 11, the hinge mechanism 9, etc. are stable. Therefore, in this refrigeration circuit, the heat load is large and the compressor 5
Even if the drive shaft 6 of 0 is rotated at high speed, the compressor 50
Noise can be prevented and high durability can be maintained.

Further, in this refrigeration circuit, since the adjusting valve 30 is built in the compressor 50, it is not necessary to secure a space for the adjusting valve 30 in the vehicle or to prepare a mounting member separately. It is easy to mount on a vehicle and is relatively inexpensive. (Embodiment 2) A refrigeration circuit according to Embodiment 2 embodies Claims 1, 3, and 6.

In this refrigeration circuit, as shown in FIG. 3, the drive shaft 6 of the compressor 60 is directly connected to the engine by a drive pulley 41, and the compressor 60 has a capacity control valve 18 of the first embodiment.
Is not provided and the air supply passage 17b is not provided. Then, in this refrigeration circuit, the discharge chamber 1 of the compressor 60
A regulating valve 31 is provided in the middle of a pipe line 50a connecting the condenser 5 and the condenser 51.

That is, the adjusting valve 31 has one end connected to the adjusting pipe 61 communicating with the crank chamber 5 of the compressor 60, and the other end connecting the adjusting pipe 61 with the pipe 50a in the vicinity of the condenser 51. The adjustment chamber 31a is connected to the control chamber 31a.
0a communicates with the discharge chamber 15 near the pilot line 63
Are connected. A valve body 31b capable of adjusting the opening degree of the air supply adjusting pipeline 61 is slidably provided in the adjusting chamber 31a, and the valve body 31b is attached in a direction of reducing the opening degree by a pressing spring 31c. It is energized.

Since other structures are the same as those of the first embodiment, the same structures are designated by the same reference numerals and detailed description thereof will be omitted. In the refrigeration circuit configured as described above, since the drive shaft 6 of the compressor 60 is directly connected to the engine by the drive pulley 41, the drive shaft 6 is driven as long as the engine is running.

Here, when the drive shaft 6 of the compressor 60 is rotated at a high speed due to the high speed operation of the engine when the heat load is large, the pilot pipe 63 side in the adjusting chamber 31a of the adjusting valve 31 is located. Between the pilot pipeline 62 and the pilot pipeline 62, a pressure difference larger than the set pressure occurs due to the flow channel resistance due to the large flow rate of the refrigerant in the pipeline 50a. In other words, the pilot line 62 side of the adjustment chamber 31a has a low discharge pressure Pd (L), and the pilot line 63 side of the adjustment chamber 31a has a high discharge pressure Pd (H).

Therefore, the valve body 31b of the adjusting valve 31 overcomes the pressing spring 31c to open the air supply adjusting conduit 61.
As a result, the refrigerant in the discharge chamber 15 is supplied to the crank chamber 5 via the pipe line 50a, the pilot pipe line 63, the adjusting chamber 31a, and the air supply adjusting pipe line 61. Therefore, the crank chamber 5
The internal pressure Pc is reliably increased, and the discharge capacity of the compressor 60 is reliably reduced.

Therefore, in the compressor 60, when the drive shaft 6 of the compressor 60 is rotated at a high speed when the heat load is large, the discharge capacity is surely reduced and periodically changed. There is no. Therefore, also in this refrigeration circuit, noise of the compressor 60 can be prevented and high durability can be maintained. Further, in this refrigeration circuit, when the drive shaft 6 of the compressor 60 is rotated at high speed when the heat load is large, the discharge capacity of the compressor 60 is reduced by the adjusting valve 31, so that the excessive cooling is performed. Etc. are prevented.

When the heat load is not so large or the drive shaft 6 of the compressor 60 is not rotated at a high speed, the flow rate of the refrigerant flowing through the pipe line 50a is small and the adjusting valve 31. A pressure difference smaller than the set pressure is not generated between the pilot conduit 63 side and the pilot conduit 62 in the adjustment chamber 31a. Therefore, the valve body 31b of the adjusting valve 31 is defeated by the pressing spring 31c to close the opening degree of the air supply adjusting conduit 61. At this time, the refrigerant in the discharge chamber 15 normally flows through the pipe line 50a. In this way, the adjusting valve 31 does not increase the pressure Pc in the crank chamber 5, and the compressor 60 is operated at the maximum discharge capacity while the swash plate 12 maintains the maximum inclination angle by the urging force of the pressing spring 13.

Since the conventional electromagnetic clutch can be omitted in this manner, the driving feeling of the vehicle can be prevented from being deteriorated when the electromagnetic clutch is connected or disconnected, and weight reduction, power consumption reduction, fuel efficiency improvement, etc. can be obtained. . (Third Embodiment) The refrigeration circuit of the third embodiment is an embodiment of claims 1, 3, and 5.

In this refrigeration circuit, as shown in FIG. 4, the compressor 50 of the first embodiment is equipped with the electromagnetic clutch 40 and the capacity control valve 18, and the discharge chamber 15 of the compressor 50 and the condenser 51 are connected to each other. The adjusting valve 32 is provided in the middle of the connecting pipe 50a. That is, in the adjusting valve 32, the first adjusting chamber 32a and the second adjusting chamber 32b are communicated with each other with the valve seat 32c therebetween. A first air supply adjusting conduit 61a communicating with the crank chamber 5 of the compressor 50 is connected to the opposite side of the first adjusting chamber 32a from the valve seat 32c. A pilot line 63 communicating with the pipe 50a in the vicinity of the discharge chamber 15 is connected to the side of the second adjustment chamber 32b opposite to the valve seat 32c, and a pipe 50a is formed on the side of the valve seat 32c of the second adjustment chamber 32b. A second air supply adjusting conduit 61b, which is communicated in the vicinity of the condenser 51, is connected. A ball 32e biased by a pressing spring 32d is provided in the first adjusting chamber 32a to close the valve seat 32c. A valve body 32f capable of opening the valve seat 32c by abutting against the ball 32e is slidably provided in the second adjustment chamber 32b, and the valve body 32f is separated from the ball 32e by a pressing spring 32g. Being energized.

Since other structures are the same as those of the first embodiment, the same structures are designated by the same reference numerals, and detailed description thereof will be omitted. In the refrigeration circuit configured as described above, the compressor 50 is driven by the high-speed operation of the engine when the heat load is large.
When the drive shaft 6 of the control valve 32 is rotating at a high speed, the pilot conduit 6 in the second control chamber 32b of the control valve 32 is
Between the third side and the second air supply adjusting pipeline 61b, the pipeline 50a is provided.
Due to the flow path resistance due to the large flow rate of the refrigerant inside, a pressure difference larger than the set pressure occurs. That is, the second adjustment chamber 32
On the side of the second air supply adjusting pipeline 61b of b, the low discharge pressure Pd
(L), the pilot conduit 63 of the second adjustment chamber 32b
The side is the high discharge pressure Pd (H).

Therefore, the valve body 32f of the adjusting valve 32 overcomes the pressing spring 32g and contacts the ball 32e, and the ball 32e overcomes the pressing spring 32d to open the valve seat 32c. As a result, the refrigerant in the discharge chamber 15 flows through the pipeline 50.
a, the second air supply adjusting conduit 61b, the second adjusting chamber 32b, the valve seat 32c, the first adjusting chamber 32a, and the first air supplying adjusting conduit 61a.
It is supplied to the crank chamber 5 via. Therefore, the pressure Pc in the crank chamber 5 is reliably increased, and the discharge capacity of the compressor 50 is reliably reduced.

Therefore, also in this refrigeration circuit, the same operation and effect as those of the first embodiment can be obtained. Further, in this refrigeration circuit, when the drive shaft 6 of the compressor 50 is normally rotated by the normal operation of the engine when the heat load is large, the flow rate of the refrigerant in the pipeline 50a is not so large. As a result, the second air supply adjusting pipeline 61b side of the second adjusting chamber 32b and the pilot pipeline 63 of the second adjusting chamber 32b.
Only a pressure difference smaller than the set pressure will occur on the side.

Since the heat load is large, the capacity control valve 18 reduces the opening of the air supply passage 17b due to the rise of the suction pressure Ps.
The pressure inside is about to be lowered. At this time, the ball 32e of the adjusting valve 32 overcomes the pressing spring 32d and the valve seat 32c, as long as the second supply air adjusting conduit 61b side of the second adjusting chamber 32b has a relatively high discharge pressure Pd (L). Open. As a result, the pressure Pc in the crank chamber 5 is reliably increased, so that even when the suction pressure Ps is high under a large heat load and the pre-pressure acting on the piston 7 is large,
Since the back pressure acting on the piston 7 can be made sufficiently large, the tilt angles of the rotary swash plate 10 and the swing swash plate 12 can be reliably reduced, and the discharge volume can be reliably reduced by reducing the stroke of the piston 7. . Therefore, even if the flow rate of the refrigerant is small, it is possible to avoid large-capacity operation under a situation where the discharge pressure is high and the durability of the compressor is reduced. (Fourth Embodiment) The refrigeration circuit of the fourth embodiment is one in which claims 1, 4, and 5 are embodied.

In this refrigeration circuit, as shown in FIG. 5, the compressor 50 of the first embodiment is equipped with the electromagnetic clutch 40 and the capacity control valve 18, and the discharge chamber 15 of the compressor 50 and the condenser 51 are connected to each other. The adjusting valve 33 is provided in the middle of the connecting pipe 50a, and the adjusting valve 33 is provided with the first and second bleed air adjusting pipes 64a, 6a.
4b are communicated. That is, in the adjusting valve 33, the first adjusting chamber 33a and the second adjusting chamber 33b have the guide hole 33 between them.
It is communicated with c. The first extraction chamber 33a has a guide hole 33c opposite to the first extraction chamber 3a, which is connected to a first extraction adjustment pipe 64a communicating with the crank chamber 5 of the compressor 50.
On the side of the guide hole 33c of 3a, a second passage communicating with the conduit 50e is formed.
The bleed air adjustment conduit 64b is connected. Second adjustment chamber 33
On the side opposite to the guide hole 33c of b, the pipe line 50a and the discharge chamber 15 are provided.
The pilot line 63 which is communicated in the vicinity is connected to the second
A pilot line 62 that communicates with the line 50a in the vicinity of the condenser 51 is connected to the guide hole 33c side of the adjustment chamber 33b. A valve body 33d is provided slidably in the second adjustment chamber 33b so as to slide along the guide hole 33c and close the first and second extraction control conduits 64a and 64b. The first and second bleed air adjustment conduits 64, 64 by the spring 33e
It is urged in a direction to increase the opening degree of b.

Since other structures are the same as those of the first embodiment, the same structures are designated by the same reference numerals and detailed description thereof will be omitted. In the refrigeration circuit configured as described above, the compressor 50 is driven by the high-speed operation of the engine when the heat load is large.
If the drive shaft 6 of the control valve 33 is rotating at high speed, the pilot conduit 6 in the second control chamber 33b of the control valve 33 is
A pressure difference larger than the set pressure occurs between the third side and the pilot conduit 62 due to the flow resistance due to the large flow rate of the refrigerant in the conduit 50a. That is, the second adjustment chamber 33b has a low-pressure discharge pressure Pd (L) on the pilot conduit 62 side, and the second adjustment chamber 33b has a high-pressure discharge pressure Pd (H) on the pilot conduit 63 side.

Therefore, the valve body 33d of the adjusting valve 33 overcomes the pressing spring 33e, and the first and second bleeding adjusting conduits 64a,
64b is closed. As a result, the refrigerant accumulated by blow-by in the crank chamber 5 is the first bleed air adjusting conduit 64a, the first bleeding chamber 33a, and the second bleed air adjusting conduit 64b.
And, it will not be led out to the suction chamber 16 via the conduit 50e. Therefore, the pressure Pc in the crank chamber 5 is reliably increased, and the discharge capacity of the compressor 50 is reliably reduced.

Therefore, also in this refrigeration circuit, the same operation and effect as those of the first embodiment can be obtained. (Fifth Embodiment) The refrigeration circuit of the fifth embodiment is an embodiment of claims 2, 4, and 5. In this refrigeration circuit, as shown in FIG. 6, the compressor 50 of the first embodiment is equipped with the electromagnetic clutch 40 and the capacity control valve 18, and a pipe connecting the evaporator 54 and the suction chamber 16 of the compressor 50. A regulating valve 34 is provided in the middle of the passage 50e, and the regulating valve 34 is connected to the first and second extraction control pipe passages 66a and 66b.

That is, in the adjusting valve 34, the first bleed air adjusting pipe line 66 communicating with the crank chamber 5 of the compressor 50 at one end thereof.
a is connected, and the other end is connected to a pipeline 50e and a pilot pipeline 65 that communicates with the vicinity of the evaporator 54.
Is formed, and the first bleeding adjustment conduit 66 of this adjustment chamber 34a is formed.
The second side which is communicated with the pipe 50e in the vicinity of the suction chamber 16 on the side of a
The bleed air adjustment conduit 66b is connected. This adjustment room 34
A valve body 34b capable of adjusting the opening degree of the first and second bleeding adjustment pipelines 66a and 66b is slidably provided in a, and the valve body 34b has a direction in which the opening degree is expanded by a pressing spring 34c. Is urged by.

Since other structures are the same as those of the first embodiment, the same structures are designated by the same reference numerals and detailed description thereof will be omitted. In the refrigeration circuit configured as described above, the compressor 50 is driven by the high-speed operation of the engine when the heat load is large.
If the drive shaft 6 is rotating at a high speed, the second bleeding adjustment conduit 66 in the adjusting chamber 34a of the adjusting valve 34 will be described.
A pressure difference larger than the set pressure is generated between the b side and the pilot conduit 65 due to the flow resistance due to the large flow rate of the refrigerant in the conduit 50e. That is, the second of the adjustment chamber 34a
The extraction adjustment pipe line 66b side has a low suction pressure Ps (L), and the adjustment chamber 34a side has a high suction pressure Ps (H).

Therefore, the valve body 34b of the adjusting valve 34 overcomes the pressing spring 34c, and the first and second bleeding adjusting conduits 66a,
66b is closed. As a result, the refrigerant accumulated by blow-by in the crank chamber 5 is prevented from being led out to the suction chamber 16 via the first extraction adjustment pipeline 66a, the adjustment chamber 34a, the second extraction adjustment pipeline 66b, and the pipeline 50e. . Therefore, the pressure Pc in the crank chamber 5 is reliably increased, and the discharge capacity of the compressor 50 is reliably reduced.

Therefore, also in this refrigeration circuit, the same operation and effect as in the first embodiment can be obtained. (Embodiment 6) A refrigeration circuit according to Embodiment 6 embodies Claims 2, 3, and 5. In this refrigeration circuit, as shown in FIG. 7, the compressor 50 of the first embodiment is equipped with the electromagnetic clutch 40 and the capacity control valve 18, and a pipe connecting the evaporator 54 and the suction chamber 16 of the compressor 50. The adjusting valve 35 is provided in the middle of the passage 50e, and the adjusting valve 35 is connected to the first and second air supply adjusting pipes 67 and 68.

That is, in the adjusting valve 35, the first adjusting chamber 3
5a and the 2nd adjustment chamber 35b have the valve seat 35c at the 1st adjustment chamber 35a side, and have a guide hole 35d and are connected between the valve seat 35c and the 2nd adjustment chamber 35b. A first air supply adjusting pipeline 67 communicating with the pipeline 50a is connected to the side of the first regulating chamber 35a opposite to the valve seat 35c. Guide hole 35
A second air supply adjusting conduit 68 communicating with the crank chamber 5 of the compressor 50 is connected to d on the valve seat 35c side. Also,
On the side opposite to the guide hole 35d of the second adjustment chamber 35b, a pipe line 50 is provided.
e is connected to the pilot line 65 that is in the vicinity of the evaporator 54, and the pilot line 6 that is in communication with the line 50e in the vicinity of the suction chamber 16 is connected to the guide hole 35d side of the second adjustment chamber 35b.
6 is connected. A ball 35f biased by a pressing spring 35e is provided in the first adjustment chamber 35a to close the valve seat 35c. In the second adjusting chamber 35b, a valve body 35g is provided slidably in contact with the ball 35f to open the valve seat 35c and to communicate the first and second air supply adjusting conduits 67 and 68. , The valve body 35g is a pressing spring 35h.
Is urged in the direction away from the ball 35f.

Since the other structures are the same as those of the first embodiment, the same structures are designated by the same reference numerals and detailed description thereof will be omitted. In the refrigeration circuit configured as described above, the compressor 50 is driven by the high-speed operation of the engine when the heat load is large.
If the drive shaft 6 of the control valve 35 is rotating at high speed, the pilot conduit 6 in the second control chamber 35b of the control valve 35 is
A pressure difference larger than the set pressure is generated between the No. 6 side and the pilot conduit 65 due to the flow resistance due to the large flow rate of the refrigerant in the conduit 50e. That is, the low adjustment pressure Ps (L) is on the pilot line 66 side of the second adjustment chamber 35b, and the high adjustment pressure Ps (H) is on the pilot line 65 side of the second adjustment chamber 35b.

Therefore, the valve element 35g of the adjusting valve 35 overcomes the pressing spring 35h and comes into contact with the ball 35f, and the ball 35f opens the valve seat 35c to open the first and second air supply adjusting conduits 6.
7 and 68 are connected. As a result, the refrigerant in the pipe 50a is supplied to the crank chamber 5 via the first air supply adjusting pipe 67, the first adjusting chamber 35a, and the second air supply adjusting pipe 68.
Therefore, the pressure Pc in the crank chamber 5 is reliably increased, and the discharge capacity of the compressor 50 is reliably reduced.

Therefore, also in this refrigeration circuit, the same operation and effect as those of the first embodiment can be obtained. In the adjusting valves 30 to 35, when the pressure difference is extremely small, the action and effect can be obtained by increasing the pressure receiving area of each valve body 22 or the like or reducing the spring constant of the pressing spring 23 or the like. can get.

[0069]

As described above in detail, since the refrigerating circuit adopts the constitution described in each claim, even if the heat load is large and the drive shaft of the compressor is rotated at a high speed, the compression circuit is compressed. It can prevent machine noise and maintain high durability.

[Brief description of drawings]

FIG. 1 shows a refrigeration circuit of a first embodiment, and is a cross-sectional overall configuration diagram of a compressor and the like.

FIG. 2 is a graph showing the relationship between the rotational speed of the drive shaft and the discharge capacity of the refrigeration circuit of the first embodiment.

FIG. 3 shows a refrigeration circuit according to a second embodiment, and is a cross-sectional overall configuration diagram of a compressor and the like.

[Fig. 4] Fig. 4 shows a refrigeration circuit of Example 3, and is a schematic cross-sectional overall configuration diagram of a regulating valve.

FIG. 5 is a refrigeration circuit according to a fourth embodiment, and is a schematic cross-sectional overall configuration diagram of a regulating valve.

6 is a refrigeration circuit according to a fifth embodiment, and is a schematic cross-sectional overall configuration diagram of a regulating valve. FIG.

[Fig. 7] Fig. 7 shows a refrigeration circuit of Embodiment 6, and is a schematic cross-sectional overall configuration diagram of a regulating valve.

FIG. 8 is an overall configuration diagram showing a conventional refrigeration circuit.

FIG. 9 is a graph showing the relationship between the rotational speed of the drive shaft and the discharge capacity of the conventional refrigeration circuit.

FIG. 10 is a graph showing the relationship between time and discharge capacity in a conventional refrigeration circuit.

[Explanation of symbols]

50, 60 ... Compressor 6 ... Drive shaft 1 ... Cylinder block 1a ... Bore 16 ... Suction chamber 15 ...
Discharge chamber 7 ... Piston 5 ... Crank chamber 10 ...
Rotating swash plate 12 ... Oscillating swash plate 17a ... Extraction passage 17b
... Air supply passage 18 ... Capacity control valve 51 ... Condenser 53 ...
Expansion valve 54 ... Evaporator 30, 31, 32, 33, 3
4, 35 ... Adjusting valve 21 ... Air supply adjusting passages 61, 61a, 61b, 67,
68 ... Air supply adjusting conduits 64a, 64b, 66a, 66b ... First and second extraction adjusting conduits 41 ... Driving pulley

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-5-306679 (JP, A) JP-A-3-986 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F04B 27/14

Claims (7)

(57) [Claims] 1. A piston that reciprocates within a bore formed in a cylinder block and a drive shaft that is driven by a drive source at a rotational speed that can fluctuate, compresses refrigerant sucked from a suction chamber and discharges it to a discharge chamber. A tilting-displaceable swash plate element that rotates with the drive shaft in the crank chamber and reduces the stroke of the piston based on an increase in pressure in the crank chamber; and bleed air that connects the crank chamber and the suction chamber. In a refrigeration circuit that includes a compressor having a passage, and circulates the refrigerant sent from the compressor via a condenser, an expansion valve, and an evaporator, between the discharge chamber and the condenser, A refrigeration circuit provided with a regulating valve for increasing the pressure in the crank chamber when the pressure difference between the upstream and downstream reaches a set pressure. 2. A piston that reciprocates within a bore formed in a cylinder block and a drive shaft that is driven by a drive source at a variable rotational speed to compress the refrigerant sucked from the suction chamber and discharge it to the discharge chamber. A tilting-displaceable swash plate element that rotates with the drive shaft in the crank chamber and reduces the stroke of the piston based on an increase in pressure in the crank chamber; and bleed air that connects the crank chamber and the suction chamber. In a refrigeration circuit that includes a compressor having a passage, and circulates the refrigerant sent from the compressor through a condenser, an expansion valve, and an evaporator, between the evaporator and the suction chamber, A refrigeration circuit provided with a regulating valve for increasing the pressure in the crank chamber when the pressure difference between the upstream and downstream reaches a set pressure. 3. The refrigeration circuit according to claim 1, wherein the regulating valve is configured to introduce the discharged refrigerant into the crank chamber when the pressure difference between the upstream and downstream sides becomes larger than the set pressure. 4. The refrigeration circuit according to claim 1, wherein the adjusting valve is configured to reduce the opening degree of the extraction passage when the pressure difference between the upstream and the downstream becomes larger than the set pressure. 5. A refrigeration circuit according to claim 1, 2, 3 or 4, wherein the compressor is provided with a capacity control valve for adjusting the pressure in the crank chamber by detecting the suction pressure. . 6. The drive shaft of the compressor is directly connected to a drive source by a drive pulley, 1, 2, 3,
The refrigeration circuit according to 4 or 5. 7. The refrigeration circuit according to claim 1, wherein the adjusting valve is built in the compressor.