WO2004061306A1

WO2004061306A1 - Swash plate-type variable displacement compressor for supercritical refrigeration cycle

Info

Publication number: WO2004061306A1
Application number: PCT/JP2003/016638
Authority: WO
Inventors: Hiroshi Kanai; Shunichi Furuya
Original assignee: Zexel Valeo Climate Control Corporation
Priority date: 2002-12-27
Filing date: 2003-12-24
Publication date: 2004-07-22
Also published as: JPWO2004061306A1; EP1586774A4; EP1586774A1; US20060083628A1

Abstract

A swash plate-type variable displacement compressor (10) used for a supercritical refrigeration cycle (1) has a rotatably installed swash plate (400), pistons (500) connected to the swash plate, and cylinders (600) movably retaining the pistons. The cylinders are provided with a suction valve (150) through which a refrigerant for the supercritical refrigeration cycle is sucked and a discharge valve (160) through which the refrigerant is discharged. The suction valve is constructed from a suction port (141) from which the refrigerant is sucked and a flexible valve body (152) mounted on the suction port. In order that the number of rotation of the swash plate is reduced at the time when the refrigerant starts to be compressed, the valve body is press-fitted in a valve seat of the suction port with the valve body elastically deformed.

Description

Satsuki Itoda β

Swash plate type variable displacement compressor for supercritical refrigeration cycle

The present invention relates to a swash plate type variable displacement compressor used for a supercritical refrigeration cycle. Background art

Various configurations are conventionally known for the intake valve and the discharge valve of a swash plate type variable displacement compressor that compresses the refrigerant of a refrigeration cycle. For example, there is known a discharge valve in which a valve body is pressed against a valve seat of a discharge port in an elastically deformed state. The structure of this type of discharge valve is also disclosed in, for example, Japanese Patent Application Laid-Open No. 61-44074 and Japanese Patent Application Laid-Open No. 2001-150300.

Furthermore, lubricating oil is mixed in the refrigerant of the refrigeration cycle, and in order to ensure good opening and closing operation of the suction valve and the discharge valve, the surface tension of the lubricating oil that goes around the gap between the valve body and the valve seat is considered. There is a need. Although the surface tension of the lubricating oil is important for ensuring the tightness of the valve, it becomes a resistance when the valve opens, so if it is larger than necessary, the operation of the valve will be delayed and the compressor will not operate. It also causes the vibration and noise of the vehicle to increase. JP-A-7-167058 and JP-A-7-168062 disclose the valve element and the valve even when the valve element is closed in order to deal with such a problem. A valve structure configured to leave a slight gap between the seat and the seat is disclosed. In the case of a swash plate type variable displacement compressor used in a refrigeration cycle, the suction valve and the discharge valve have been given importance in such a configuration as to prevent vibration and noise.

Now, as the refrigerant of the refrigeration cycle, so far the refrigerant off port emissions system including alternate off Russia emissions have been widely adopted in recent years in consideration of the global environment, for changing this to C 0 ₂ Development is being done. Cool C 0 ₂ The internal pressure of a refrigeration cycle that uses a medium is extremely high when compared to a refrigeration cycle that uses a chlorofluorocarbon-based refrigerant.In particular, the pressure on the high-pressure side may exceed the critical point of the refrigerant depending on operating conditions such as air temperature. is there. The critical point is the limit on the high-pressure side where the gas and liquid layers coexist (that is, the limit on the high-temperature side), and is the end point of one of the vapor pressure curves. The pressure, temperature and density at the critical point are the critical pressure, critical temperature and critical density, respectively. In particular, in the radiator of the refrigeration cycle, when the pressure exceeds the critical point of the refrigerant, the refrigerant does not condense. This type of supercritical refrigeration cycle is installed in, for example, an automobile and used for air conditioning in a vehicle.

Further, a compressor used in a supercritical refrigeration cycle is also described, for example, in Japanese Patent Application Publication No. 2002-25707. The compressor described in this publication is configured such that the stroke of the piston can be changed according to the inclination of a swash plate provided rotatably. The piston is held by the cylinder so as to be able to reciprocate, and the cylinder is provided with a suction valve for sucking the refrigerant and a discharge valve for discharging the refrigerant. The refrigerant circulating in the refrigeration cycle is drawn into the cylinder from the suction valve, compressed, and discharged from the discharge valve to the outside of the cylinder. In the case of a refrigeration cycle for in-vehicle air conditioning, the compressor is connected to a power engine of a vehicle and is operated by the power of the power engine.

By the way, the supercritical refrigeration cycle is significantly different from the conventional chlorofluorocarbon-based refrigeration cycle in terms of pressure resistance, and the compressor for the supercritical refrigeration cycle also has a superior structure based on the pressure resistance and other factors. A creative ingenuity is required.

For example, according to the above-mentioned Japanese Patent Publication No. 200-02-2577003, in the case of a compressor for a supercritical refrigeration cycle, since the operating pressure is high, the refrigerant through a small gap is required. Leakage can also cause performance degradation. The compressor described in the publication has an elastic member that presses the valve element of the suction valve against the valve seat to eliminate a gap generated between the valve element and the valve seat. However, when an elastic member for pressing the valve body against the valve seat is provided, the number of parts is increased, so that there is a disadvantage that the structure is complicated, refined, and the cost is increased. In addition, according to the durability test of the inventor of the present invention, it has been found that such an elastic member is a problem in which deterioration of durability and the like are difficult to avoid.

Furthermore, in the case of a supercritical refrigeration cycle, it is important for a compressor that operates with the power of the vehicle's power engine to ensure startability when starting the drive engine. In other words, such a compressor has a relatively small cylinder volume due to a pressure resistance problem as compared with a refrigeration cycle compressor using a chlorofluorocarbon-based refrigerant. Where the effect of medium leakage is significant, the seat surfaces of the valve body and the valve seat also become narrower, and lubricating oil flowing between them tends to be insufficient, making it difficult to ensure good opening and closing operation of the valve body. There is also a problem. Insufficient oil due to such a shortage of oil causes delay in the suction and discharge of the refrigerant, especially when the pressure is balanced (when the flow rate of the refrigerant is very small). It is considered that the number of revolutions at startup, that is, the number of revolutions of the swash plate when the refrigerant started to be compressed, was higher than necessary.

Also, as a compressor mounted on a vehicle, a clutchless compressor connected to a driving engine of the vehicle without using a clutch is known. In the case of a clutchless compressor, its swash plate rotates constantly even when the refrigerant is not compressed, and the minimum stroke of the piston is usually about 5% or less of the maximum stroke. I have. In recent years, it has become a very important issue for such a clutchless compressor to reduce the number of revolutions at startup.

In particular, in the case of a supercritical refrigeration cycle, the pressure of the refrigerant when the compressor is started is about 7.2 MPa in a 30 ° C atmosphere. On the other hand, in the case of a refrigeration cycle using a chlorofluorocarbon-based refrigerant, the pressure of the refrigerant when the compressor is started is about 0.67 MPa under a 30 ° C atmosphere. Become. Therefore, in the compressor of the supercritical refrigeration cycle, high pressure resistance is secured by setting the volume of the cylinder and the opening area of the port small. If common ones, in the case of co-compressors of a supercritical refrigeration cycle, the bore diameter of the silicon Sunda is 1 5. 0~ 2 1. 0 mm, the volume of Siri Sunda is 2 0~ ³ 3 cm 3, inhalation the opening area of the port in the valve and discharge valve are 7. 0~ ² 9. 0 mm 2. In contrast, in the case of a compressor of a refrigeration cycle using chlorofluorocarbon-based refrigerant, Bo § the diameter of the silicon Sunda is 3 2 to 4 0 mm, the volume of Siri Sunda is ^{9 0 cm 3 ~ 1 7 0} cm 3, intake valves and the opening area of the port at the discharge valve 3 8.5 - a 1 1 3. 0 mm ^2..

Also, in such a supercritical refrigeration cycle compressor or a refrigeration cycle compressor using a chlorofluorocarbon-based refrigerant, if the processing accuracy of the cylinder and biston is the same, then in the case of the supercritical refrigeration cycle, the biston will be The ratio of the gap between the cylinder and the biston to the volume of the cylinder at the upper fulcrum becomes relatively large. This is also one of the causes of the increase in the number of revolutions of the supercritical refrigeration cycle at startup.

The present invention has been made in view of such circumstances, and an object thereof is to achieve an improvement in performance of a swash plate type variable displacement compressor for a supercritical refrigeration cycle. Disclosure of the invention

The invention described in claim 1 of the present application is a compressor used in a supercritical refrigeration cycle, wherein the swash plate is rotatably provided, a piston connected to the swash plate, and the piston is moved. A swash plate type variable capacity compressor comprising: a suction valve for sucking the refrigerant of the supercritical refrigeration cycle; and a discharge valve for discharging the refrigerant. The suction valve is provided with a flexible valve body at a suction port for sucking the refrigerant, and the swash plate type variable capacity compressor rotates the swash plate when the refrigerant starts to be compressed. Reduce number A swash plate type variable displacement compressor having a configuration in which the valve body is pressed against the valve seat of the suction port in an elastically deformed state. According to such a configuration, the performance of the swash plate type variable displacement compressor for the supercritical refrigeration cycle is surely improved.

The inventor of the present application conducted various trial manufactures and experiments on various valve structures in order to obtain a suitable valve structure in a swash plate type variable displacement compressor for a supercritical refrigeration cycle. According to the same experiment, in order to eliminate the gap between the valve element and the valve seat as described above, the suction valve is more important than the discharge valve from the viewpoint of reducing the number of revolutions at startup. There was found. In addition, the suction valve, which was the most effective in securing startability, durability, and good opening and closing operations of the valve element, has flexibility in the suction port for sucking refrigerant. The valve body was mounted, and the valve body was pressed against the valve seat of the suction port with a slight elastic deformation. The valve element of the suction valve is designed in consideration of appropriate internal stress after being mounted on the suction port.

According to such a configuration, even if the seat surfaces of the valve element and the valve seat are slightly narrow, it is possible to efficiently avoid the defective seats. As a result, the rotational speed of the swash plate when the refrigerant starts to be compressed is reliably reduced.

An experimental comparison between the case where the suction valve was elastically deformed against the valve seat and the case where the suction valve was not pressed, and the number of rotations at the time of startup when pressure was applied, the start when no pressure was applied. The rotation speed at that time was 30 to 70%. That is, in the present invention, reducing the rotation speed of the swash plate when the refrigerant starts to be compressed is based on a comparison with a case where the valve body of the suction valve is elastically deformed to the valve seat and is not pressed against the valve seat. It is.

As described above, the present invention focuses on a very important structure in the details of the swash plate type variable displacement compressor used in the supercritical refrigeration cycle, and as a result, with a very simple structural device, This is a swash plate type variable displacement compressor that has achieved a remarkable effect of dramatically improving the performance of such a compressor.

In the invention described in claim 2 of the present application, in claim 1, the valve body is The swash plate type having a configuration in which the deflection of the valve body when the suction port is attached is lmm or less and the external force received by the valve body from the valve seat of the suction port is 1.8 N or less at this time. It is a variable capacity compressor. That is, if the deflection of the valve body is set to 1 mm or less and the external force that the valve body receives from the valve seat of the suction port is set to 1.8 N or less, the valve body can be smoothly opened and closed while maintaining the opening and closing operation. It is possible to ensure good seating properties between the valve and the valve seat.

The invention described in claim 3 of the present application is the invention according to claim 1 or 2, wherein the supercritical refrigeration cycle is a refrigeration cycle for air conditioning in a vehicle mounted on an automobile, and the swash plate type variable displacement compressor includes a clutch. A swash plate type variable displacement compressor configured to be a clutchless compressor that is connected to the drive engine of the vehicle without intervention. That is, the swash plate type variable displacement compressor of the present invention reliably reduces the number of revolutions of the swash plate when the refrigerant starts to be compressed, and as a clutchless compressor used in a refrigeration cycle for air conditioning in a vehicle, It can be used very suitably. BRIEF DESCRIPTION OF THE FIGURES

Figure 1

FIG. 1 is a schematic diagram showing a supercritical refrigeration cycle according to an embodiment of the present invention. Figure 2

FIG. 2 is a cross-sectional view showing a swash plate type variable displacement compressor for a supercritical refrigeration cycle according to an embodiment of the present invention.

Fig 3

FIG. 2 is a front view showing a valve plate and a cylinder-side valve element plate according to the embodiment of the present invention.

Fig. 4

FIG. 2 is a front view showing a valve plate and a valve plate on a rear housing side according to the embodiment of the present invention. Fig. 5

FIG. 3 is a cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. Fig. 6

FIG. 2 is an exploded cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. Fig. 7

FIG. 3 is a cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. Fig. 8

FIG. 3 is a cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. Fig. 9

4 is a comparison graph of the number of revolutions at the time of startup before and after the improvement according to the embodiment of the present invention.

Fig. 10

FIG. 3 is a cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. Fig. 1 1

FIG. 2 is an exploded cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. Fig. 1 2

FIG. 3 is a cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. Fig. 13

FIG. 2 is an exploded cross-sectional view illustrating a suction valve and a discharge valve according to the embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, examples of the present invention will be described. As shown in FIG. 1, the supercritical refrigeration cycle 1 of the present embodiment is a refrigeration cycle for in-vehicle air conditioning mounted on an automobile, and includes a swash plate type variable capacity compressor 10 for compressing a solvent, and the compressor 10 A radiator 20 for cooling the refrigerant compressed by the radiator 20, an expansion valve 30 for decompressing and expanding the refrigerant cooled by the radiator 20, and an evaporator 4 for evaporating the refrigerant decompressed by the expansion valve 30. 0, an accumulator 50 that separates the refrigerant flowing out of the evaporator 40 into a gas phase and a liquid phase and sends the gas phase refrigerant to the compressor 10, and a high-pressure refrigerant and a low-pressure refrigerant. Internal heat exchanger that improves cycle efficiency by exchanging heat

6 0. Is a refrigerant is used a C 0 _2, the pressure of the high pressure side of the supercritical refrigeration cycle 1, Ri by the use conditions such as air temperature, exceed the critical point of the refrigerant. The refrigerant contains lubricating oil for facilitating the driving of the compressor 10.

As shown in FIG. 2, the swash plate type variable displacement compressor 10 of this example includes a front nozzle 110, a cylinder block 120, a rear nozzle 130, and a valve plate. 140, rotatable drive shaft 200, lug plate 300 provided in drive shaft 200, drive shaft 200, and lug plate 300 The swash plate 400, the piston 500 connected to the swash plate 400 via the bus 410, and the cylinder 6 for holding the piston 500 reciprocally. 0 0 and a control valve 700 for controlling the pressure acting on the biston 500.

The swash plate type variable capacity compressor 100 is configured such that the swash plate 400 rotates together with the drive shaft 200 and the lag plate 300 and the piston 500 reciprocates, whereby a series The refrigerant is sucked into the compressor 600, compressed and discharged, and the control valve 700 controls the pressure acting on the piston 500, whereby the swash plate 400 is controlled. The stroke of the piston 500 changes with the inclination of 0 to control the refrigerant discharge amount. The minimum stroke of BISTON 500 is set at about 5% or less of the maximum stroke. A plurality of screws 500 and a plurality of cylinders 600 are arranged at equal intervals around the rotation axis of the drive shaft 200.

The drive shaft 200 is mounted on the front housing 110 and the cylinder block 120 via a bearing. The drive shaft 200 is connected to the engine, which is the drive engine of the vehicle, without going through a clutch. That is, the swash plate type variable capacity compressor 10 is a so-called clutchless compressor. Front Tohau The inside of the jing 110 is a crank chamber 111 provided with a lug plate 300 and a swash plate 400. The cylinder block 120 is a member constituting a plurality of cylinders 600.

The lag plate 300 is a member fixed to the drive shaft 200, and an arm portion 310 for connecting the swash plate 400 is provided at a key portion thereof. The swash plate 400 is provided with a guide section 420 to which a shroud 410 is mounted, and is mounted to the drive shaft 200 so that the slide can be moved and the inclination angle can be changed. I have. In addition, between the lug plate 300 and the swash plate 400, there is provided a spring 430 that urges the swash plate 400 and the biston 500 to a certain extent on the cylinder 600 side. Have been.

Each of the bistons 500 is anchored to the cylinder 410 and is in contact with the bores 6100 of the cylinder 600. Reciprocate each time.

The control valve 700 controls the internal pressure of the crankcase 111. The inclination of the swash plate 400 and the stroke of the biston 500 change according to the internal pressure of the crankcase 111.

The valve plate 140 is a member that forms a suction valve 150 that sucks refrigerant into the cylinder 600 and a discharge valve 160 that discharges refrigerant from the cylinder 600. It is arranged between 20 and the rear housing 130. Further, on both sides of the valve plate 140, a cylinder-side valve body plate 151 and a rear housing-side valve body plate 161 which will be described in detail later are mounted by screws. By disposing such a valve plate 140 in each cylinder 120, a suction valve 150 and a discharge valve 160 are provided, respectively. The coolant is compressed between the piston 500 and the valve plate 140.

The rear housing 130 is provided with a control valve 700 and a suction chamber 1311 and a discharge chamber 1332 between the control housing and the valve plate 140. In addition, flow passages through which the refrigerant flows are provided at key points of the compressor 1, and the low-pressure gas that has circulated through the refrigeration cycle 1 before being compressed is introduced into the suction chamber 13 1. The low-pressure gas in the suction chamber 13 1 is sucked into the cylinder 600 from the suction valve 150 when biston 500 moves back, and becomes high-pressure gas when biston 500 moves further forward. From the discharge port 160 to the discharge chamber 132. The high-pressure gas in the discharge chamber 132 circulates through the refrigeration cycle again.

The control valve 700 is communicated with the crank chamber 11 1, the suction chamber 13 1, and the discharge chamber 13 2 through predetermined flow paths, and when the pressure of the low-pressure gas decreases, When the bellows provided therein expands, the valve moves and the high-pressure gas is led to the crank chamber 11. When the pressure of the low-pressure gas rises, the pulp closes due to the contraction of the bellows, and the high-pressure gas guided to the crankcase 11 is cut.

The swash plate 400 reciprocates in a state where the average of the internal pressure of each cylinder 600 and the internal pressure of the crankcase 111 are balanced. That is, the inclination of the swash plate 400 and the stroke of the biston 500 are controlled by the valve opening of the control valve 700, and the discharge amount of the high-pressure gas is controlled by the piston. It increases as the stroke of 500 increases and decreases as the stroke decreases.

The pressure of the refrigerant at the time of starting the swash plate type variable capacity compressor 10 is about 7.2 MPa in a 30 ° C atmosphere. Further, the diameter of the bore 6 1 0 Siri Sunda 6 0 0 1 5. 0 to 2 1. 0 mm, the volume of silicon Sunda 6 0 0 2 0~ ³ 3 cm 3, the intake valve 1 5 0 and a discharge valve The opening area of each of the ports 14 1 and 142 in 16 0 is 7.0-29.0 mm ² .

Next, the valve structure in the present example will be described with reference to FIGS. The valve plate 140 has a plurality of suction ports 141 communicating each cylinder 600 and the suction chamber 131, and each cylinder 600 and the discharge chamber 132. And a plurality of discharge ports 1 and 2 communicating with each other. In addition, the cylinder valve plate 15 1 has a valve body 15 2 of the suction valve 150 corresponding to each suction port 14 1, and a hole 15 3 corresponding to each discharge port 14 2. And a plurality of members. Further, on the rear housing side, the valve plate 16 1 has a valve 16 2 of the discharge valve 16 corresponding to each discharge port 14 2, and a hole 16 corresponding to the suction port 14 1. 3 and a plurality of such members (see FIGS. 3 and 4).

The suction valve 150 of the present example has a flexible valve element 152 mounted on a suction port 141 for sucking a refrigerant into a cylinder 600. The valve element 152 of the suction valve 150 is pressed against one surface of the valve plate 140 serving as a valve seat of the suction port 141 in a slightly elastically deformed state. Similarly, the discharge valve 160 of the present example has a flexible valve element 162 attached to a discharge port 142 that discharges refrigerant from the inside of the cylinder 600. . The valve element 162 of the discharge valve 160 is pressed against the other surface of the valve plate 140 serving as the valve seat of the discharge port 142 in a slightly elastically deformed state. Reference numeral 164 in the figure denotes a retainer that regulates the opening of the valve element 162 of the discharge valve 160. The retainer 164 is screwed to the valve plate 140 (see FIG. 5).

In other words, the valve element 152 of the suction valve 150 provided on the cylinder side valve element plate 151 is plastically deformed in a curved shape with the tip protruding toward the valve plate 140. (Refer to Fig. 6.) The cylinder side plate plate 151 is attached to the valve plate 140, and it is forcibly elastically deformed. The valve element 152 is plastically deformed by press working, and the deflection 3 when attached to the suction port 141 is 1 mm or less (more specifically, 50 to 200 2111). Has become. The plate thickness of the material of the valve element 152 of the suction valve 150 is desirably 0.2 to 0.3 mm, and is 0.25 mm in this example. Its modulus of longitudinal elasticity of the material, 2. a ^{0 6 XI 0 5 N / mm} 2 before and after. And the valve element 1 5 2 of the suction valve 150 The external force P received from the valve seat of port 14 1 is 1.8 N or less in order to ensure the smooth opening and closing operation of valve body 152. The more desirable range of the external force P is 1.2 N or less, and the most desirable range is 0.2 to 0.7 N. For example, if the spring constant k of the valve element 152 is about 5.0 N / mm and the deflection 5 丄 is 240 m, the external force P is k = P / d, and Become. Alternatively, if the spring constant k of the valve element 152 is about 4.0 N / mm and the deflection is 150 / m, the external force P is about 0.6 N. The spring constant k depends on the longitudinal elastic modulus of the material and the shape of the valve element 152.

The basic structure of the valve element 162 of the discharge valve 160 provided on the rear housing-side valve element plate 161 is the same as the above-described valve element 152 of the suction valve 150. That is, the valve body 1 6 2 flexure (5 ₂ of the discharge valve 1 6 0 is equal to or less than lmm, the external force P that the valve body 1 6 2 of the discharge valve 1 6 0 receives from port 1 4 2 of the valve seat Is 1.8 N or less.

In addition, a coating such as PTFE is applied to the surface of each of the valve elements 15 2 and 16 2 in order to improve seating with the valve seat. The valve element 15 2 of the suction valve 15 0 and the valve element 16 2 of the discharge valve 16 0 are opened and closed by the differential pressure of the crank chamber 1 1 1, the suction chamber 1 3 1, and the discharge chamber 1 3 2 respectively. It works (see Figs. 7 and 8).

The inventor of the present application repeated a comparison experiment of the number of revolutions at the time of startup between the swash plate type variable displacement compressor 10 of the present example and the cylinder side valve plate 151, which was replaced, under different conditions. went. The replaced cylinder-side valve body plate is flat, and the valve body 150 of the suction valve 150 is elastic on the surface of the valve plate 140, which is the valve seat of the suction port 141. It is not pressed in a deformed state. As a result, the rotation speed at startup of the swash plate type variable displacement compressor 10 of this example is 30 to 70% lower than the rotation speed at startup of the cylinder-side valve plate 151, which has been replaced. It was within the range of the center. For example, when the valve element of the suction valve is not pressed against the valve seat while being elastically deformed, the rotation speed at startup is 700 rp By replacing the valve body of a swash plate type variable displacement compressor of about m and pressing it against the valve seat while slightly deforming it, the rotational speed at startup was reduced to about 300 rpm. Figure 9 is a comparison graph of the number of revolutions at startup before and after replacement of the valve element of the intake valve, that is, before and after the improvement. According to such an experiment, it has been proved that the swash plate type variable capacity compressor 10 of the present example has a surely reduced rotation speed of the swash plate when the refrigerant starts to be compressed.

The shape of the valve element 152 of the suction valve 150 and the shape of the valve element 162 of the discharge valve 160 can be changed as appropriate, and are not limited to those illustrated in the drawings. Of course. For example, as shown in FIG. 10 and FIG. 11, the valve body 15 2 of the suction valve 150 or the valve body 16 2 of the discharge valve 160 has a tip formed into a hemispherical shape, and has a circular shape. It is also possible that the spherical surface is in contact with the edge of the suction port 141 or the discharge port 142. The tip is preferably formed by pressing. For the valve element 15 2 of the suction valve 150 or the valve element 16 2 of the discharge valve 160, the male threaded part B passing therethrough is screwed into the female thread N provided on the valve plate 140. As a result, the distal end portion is elastically deformed in a state of being pressed against the edge of the suction port 141 or the discharge port 142.

Alternatively, as shown in FIGS. 12 and 13, the flat valve elements 15 2 and 16 2 are elastically deformed and pressed against the surface of the curved valve plate 140. It is also possible. In this case, plastic deformation of the valve bodies 15 2 and 16 2 can be omitted. Industrial applicability

INDUSTRIAL APPLICABILITY The swash plate type variable displacement compressor of the present invention can be suitably used as a compressor for a supercritical refrigeration cycle in which the pressure on the high pressure side exceeds the critical point of the refrigerant.

Claims

Scope of Word

1. A compressor used for a supercritical refrigeration cycle, comprising: a swash plate rotatably provided; a biston connected to the swash plate; and a cylinder movably holding the biston. In the swash plate type variable displacement compressor, the cylinder includes a suction valve that sucks a medium of the supercritical refrigeration cycle, and a discharge valve that discharges the refrigerant.

The suction valve has a flexible valve body mounted on a suction port for sucking the refrigerant,

The swash plate type variable displacement compressor may be configured so that the valve body is elastically deformed and pressed against a valve seat of the suction port so as to reduce the rotation speed of the swash plate when the refrigerant starts to be compressed. Features a swash plate type variable displacement compressor.

2. The deflection of the valve body when the valve body is attached to the suction port is 1 mm or less, and the external force received by the valve body from the valve seat of the suction port at this time is 1.8 N or less. The swash plate type variable displacement compressor according to claim 1, wherein:

3. The supercritical refrigeration cycle is a refrigeration cycle for in-vehicle air conditioning mounted on a vehicle, and the swash plate type variable displacement compressor is a clutchless compressor connected to a driving engine of the vehicle without using a clutch. The swash plate type variable displacement compressor according to claim 1 or 2, wherein: