JP2003097445A - Linear compressor for co2 refrigerant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote efficiency for a linear compressor for CO2 refrigerant by improving the sealing performance of a delivery valve under high differential pressure conditions without using lubrication oil, and to attain noise reduction by relaxing a collision force between the delivery valve and a valve plate. SOLUTION: Adhesiveness between a delivery valve 13 and a valve plate 11 is increased by placing a sealing member 18 on an opening/closing surface part 16 of the delivery valve 13 and the leakage from the delivery valve 13 to the valve plate 11 is reduced and efficiency is highly promoted. Noise reduction is also attained by relaxing the collision force between the delivery valve 13 and the valve plate 11 by the sealing member 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear compressor that reciprocates a piston incorporated in a cylinder by a linear motor to suck and discharge CO2 refrigerant gas.

[0002]

2. Description of the Related Art In a refrigerating cycle, an HCFC refrigerant represented by R22 is said to destroy the ozone layer due to its stable physical properties. In recent years, HCFC
An HFC-based refrigerant is used as an alternative refrigerant to the system-based refrigerant, and this HFC-based refrigerant has a property of promoting a warming phenomenon. Therefore, recently, natural refrigerants that do not significantly affect the destruction of the ozone layer and the global warming phenomenon have begun to be adopted. However, among natural refrigerants, HC-based refrigerants are flammable and thus ignite, and CO2 refrigerants are high-pressure working gases, so it is necessary to prevent explosion from the viewpoint of ensuring safety. Therefore, it is required to reduce the amount of refrigerant used as much as possible. On the other hand, the HC refrigerant has no lubricity as a refrigerant itself and has a property of easily dissolving in a lubricant.

From the above, when using a natural refrigerant, an oilless or oil poor type compressor is required. Therefore, the linear compressor, which has a small load acting in the direction orthogonal to the axis of the piston and a small sliding surface pressure, is oilless compared to the reciprocating compressors, rotary compressors, and scroll compressors that have been used more often than before. It is known as a type of compressor that is easy to achieve.

[0004]

However, if the CO2 refrigerant is made oilless in particular, there is a problem that mainly the sealing property of the intake and discharge valves is disadvantageous and the compression efficiency is lowered.
Further, since the amount of displacement of the valve also increases, the noise generated when the valve collides with the valve plate is large, and it is necessary to avoid this.

In view of the above circumstances, according to the present invention, even under high differential pressure and oilless conditions, by utilizing the sealing means at the opening / closing surface of the discharge valve, the refrigerant gas is transferred from the gap between the discharge valve and the valve plate to the cylinder. It is an object of the present invention to provide a linear compressor for a CO2 refrigerant that suppresses leakage and has high efficiency.

Another object of the present invention is to provide a linear compressor for a CO2 refrigerant which has a low noise by grounding the valve with a sealing material to reduce the collision force between the discharge valve and the valve plate.

Further, when the discharge valve is closed, the repulsive force of the spring body is applied to the discharge valve to forcibly bring the discharge valve into contact with the valve plate, thereby increasing the degree of close contact between the valve and the valve plate and providing a sealing property. It is an object of the present invention to provide a more efficient linear compressor for CO2 refrigerant by increasing the temperature.

[0008]

According to a first aspect of the present invention, there is provided a closed container, a head cover portion and a cylinder formed inside the closed container, a linear motor fixed to the cylinder, and a cylinder. A piston plate slidably supported along the axial direction, a compression chamber provided between the piston and the head cover portion, and a valve plate provided with a discharge hole for guiding discharge of the refrigerant compressed in the compression chamber. And a linear compressor for a CO2 refrigerant having a discharge valve for opening and closing the discharge hole, wherein a seal member is arranged on the opening / closing surface of the discharge valve without using lubricating oil. When the discharge valve closes the discharge hole, the discharge valve comes into contact with the valve plate while deforming and compressing the seal member, so that the discharge valve and the valve plate are in a close contact state, and the sealing property is improved. In particular, by disposing the seal member in the entire portion where the discharge valve is in contact with the valve plate, the sealing performance can be further improved as compared with the conventional free valve and cantilever valve. At the same time, the collision force between the discharge valve and the valve plate can be reduced.

According to a second aspect of the present invention, a concave portion is provided on the valve plate side of the opening / closing surface portion of the discharge valve according to the first aspect of the invention, and an O ring is formed in the concave portion. When the discharge valve closes the discharge hole, the discharge valve contacts the valve plate while deforming and compressing the seal member, so that the discharge valve and the valve plate are in a close contact state, and the sealing performance can be improved.

According to a third aspect of the present invention, the sealing member in the second aspect of the present invention is a butadiene / acrylonitrile copolymer, chlorosulphonated polyethylene, hexafluoropropylene / vinylidene fluoride copolymer, etc. It is made of rubber. Since these rubber materials are excellent in heat resistance, aging resistance and wear resistance, the sealing performance can be further improved.

According to a fourth aspect of the present invention, the discharge valve according to the first aspect of the present invention is provided with a resin coating, whereby the discharge valve is closed when the discharge valve closes the discharge hole. Since the resin coating is deformed and compressed and comes into contact with the valve plate, the discharge valve and the valve plate are brought into close contact with each other, and the sealing performance can be improved.

According to a fifth aspect of the present invention, in the first aspect, the second aspect, the third aspect, or the fourth aspect, the discharge valve is pressed and supported by a spring body. By applying the spring force of the spring body to the discharge valve, the discharge valve is forcibly grounded to the valve plate, the degree of contact between the discharge valve and the valve plate is improved, and as a result, the sealing performance is enhanced.

According to a sixth aspect of the present invention, the coil spring is used as the spring body in the fifth aspect of the invention. Thereby, the sealing performance can be improved.

According to a seventh aspect of the present invention, in the fifth aspect of the invention, a leaf spring is used as the spring body. Thereby, the sealing performance can be improved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a linear compressor of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view showing the overall configuration of a linear compressor according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the main parts around the discharge valve in the discharge stroke of the same embodiment. FIG. 3 is a cross-sectional view of the main parts around the discharge valve during the intake stroke of the same embodiment.

First, the overall structure of the linear compressor according to the present embodiment will be described with reference to FIGS. This linear compressor is roughly classified into a cylinder 3 supported by a support mechanism portion 2 in a closed container 1, a piston 4 slidably supported by the cylinder 3 along its axial direction, and an axial direction of the piston 4. A linear motor portion 6 having a spring member 5 that contributes to the force of the cylinder 3 and a fixed portion 6a fixed to the cylinder 3 side and a movable portion 6b that is reciprocally supported in a reciprocating path formed in the fixed portion 6a. A connecting rod 7a, which is one of the connecting mechanism parts 7 connected to the piston 4, and a head cover part 9 for letting the refrigerant into and out of the compression chamber 8 side of the cylinder 3. One end of the connecting rod 7a is connected to the spring member 5, and the movable portion 6b is also connected to the spring member 5.

The closed container 1 is composed of a container for housing the main constituent elements of the linear compressor, and a refrigerant is supplied to a space 1a inside the container from a suction pipe (not shown) and introduced into the suction side of the head cover 9. It Further, the compressed refrigerant is discharged outward from the head cover 9 side through a discharge pipe (not shown) connected to the closed container 1.

The support mechanism section 2 comprises a spring support plate 2a fixed inside the closed container 1 and a plurality of coil springs 2b mounted on the spring support plate 2a and supporting the cylinder 3. It should be noted that the coil spring 2b extends from the cylinder 3 to the closed container 1
It functions to prevent vibration transmitted to the.

The cylinder 3 is integrally formed with a flat flange portion 3a against which the coil spring 2b abuts, and a boss portion 3b protruding from the center of the flange portion 3a toward one end side (upward in FIG. 1). It consists of things. In addition, as shown in the figure, the cylinder 3
A compression chamber 8 is formed between the head cover 9 and the tip 4 a of the piston 4, which are closely connected to the collar 3 a of the piston 4.

The piston 4 has an outer peripheral surface 4b slidably supported on the inner peripheral surface 3c of the cylinder 3, and the inner surface is a recess 4d whose center of gravity is located at the bottom 4c.

As shown in FIG. 1, the spring member 5 is made of a disk-shaped member in the present embodiment, and has a structure in which it is elastically deformed from the peripheral edge to the central portion when the peripheral edge is fixed.

The linear motor section 6 comprises a fixed section 6a and a movable section 6b. The fixed portion 6a includes an inner yoke 6c and an outer yoke 6d. The inner yoke 6c is formed of a cylindrical body, and is fixed to the boss portion 3b of the cylinder 3 by external contact. A coil 10 is housed inside the inner yoke 6c and is connected to a power source (not shown). On the other hand, the outer yoke 6d is a cylindrical body that covers the inner yoke 6c,
It is fixed to the collar portion 3a of the cylinder 3. In addition, a reciprocating path of a minute space is formed between the inner peripheral surface of the outer yoke 6d and the outer peripheral surface of the inner yoke 6c. Further, in the present embodiment, the outer yoke 6d supports and fixes the peripheral edge side of the spring member 5.

The movable portion 6b of the linear motor portion 6 comprises a permanent magnet 6g and a cylindrical holding member 6h for holding the permanent magnet 6g. The cylindrical holding member 6h is reciprocally housed in the reciprocating path, and is formed of a disk portion 6j integrally connected to a peripheral edge portion 6i for fixing the permanent magnet 6g. Also, the disc portion 6j
The central part of is fixed to the central part of the spring member 5. In addition,
The permanent magnet 6g is arranged at a position facing the coil 10,
A small gap is formed between them. The inner yoke 6c and the outer yoke 6d are arranged on a concentric circle in order to uniformly maintain this minute gap over the entire circumference.

The connecting rod 7a of the connecting mechanism portion 7 is composed of an elongated rod-shaped member, and the piston 4 is provided at one end portion on the lower side of the drawing, and the other end portion at the upper side is the center of the disc portion 6j of the cylindrical holding member 6h. And is fixed to the central part of the spring member 5. The connection of the other end is formed in a detachable structure by the bolt 7b in this embodiment.

The head cover portion 9 is fixed to the end face side of the collar portion 3a of the cylinder 3 via the valve plate 11. A suction valve 12, a discharge valve 13, a discharge stopper 13a, etc., which can communicate with the compression chamber 8 are assembled to the valve plate 11, and these are installed in a suction side space 14 and a discharge side space 15 provided inside the head cover portion 9. Each is connected. Further, the discharge hole 11a which is a passage connecting the discharge side space 15 and the compression chamber 8
Is also configured on the valve plate 11.

Reference numeral 16 denotes an opening / closing surface of the discharge valve 13, a recess 17 is provided on the opening / closing surface 16 on the valve plate 11 side, and a sealing member 18 is closely formed in the recess 17. In this embodiment, the O-ring 1 is used as the seal member.
8a is used. This facilitates assembly in mass production.

The suction pipe and the discharge pipe (not shown) provided on the closed container 1 side are connected to the suction side space 14 and the discharge side space 15, respectively.

The operation of the linear compressor configured as described above will be described below.

First, when the coil 10 of the fixed portion 6a is energized, a thrust force proportional to the current is generated between the movable portion 6b and the permanent magnet 6g according to Fleming's left-hand rule.
Due to the generation of this thrust, a driving force that moves along the axial direction acts on the movable portion 6b. Cylinder holding member 6 of movable part 6b
Since h is connected to the spring member 5 together with the connecting rod 7a, the piston 4 moves. Where the coil 10
Power is applied to the linear motor 6 by a sine wave, and forward and reverse thrusts are alternately generated in the linear motor unit 6. Then, the piston 4 reciprocates by the forward and reverse thrusts that are alternately generated.

The refrigerant is introduced into the closed container 1 through the suction pipe. The refrigerant introduced into the closed container 1 enters the compression chamber 8 from the suction side space 14 of the head cover portion 9 through the suction valve 12 assembled to the valve plate 11. After that, it is discharged from the discharge valve 13 through the discharge hole 11a, the discharge side space 15 of the head cover 9 and a discharge pipe (not shown) to the outside.

Here, looking at the behavior of the discharge valve 13 in the discharge and suction strokes during a series of reciprocating movements of the piston 4, the discharge valve 13 receives a differential pressure during the discharge stroke and bends upward in FIG. Deform. Next, in the suction stroke, as the piston 4 moves in the direction opposite to the head cover portion 9, the pressure in the compression chamber 8 decreases with respect to the pressure in the discharge side space 15, so the discharge valve 13 Approaching the valve plate 11,
Further pressing the O-ring 18a, the valve plate 11
(See Fig. 3).

Therefore, the sealing performance of the discharge valve 13 can be remarkably improved under a high differential pressure of CO2 refrigerant or the like and oilless condition, and the leakage loss during the suction stroke can be reduced to realize a highly efficient compressor. . Further, by reducing the collision force between the discharge valve 13 and the valve plate 11, noise reduction can be realized.

As described above, in the linear compressor for CO2 refrigerant according to the present embodiment, the seal member 18 is arranged on the opening / closing surface portion 16 of the discharge valve 13 without using the lubricating oil. The sealability of 13 can be remarkably improved, and the leakage loss at the time of the suction stroke can be reduced to improve the efficiency. Further, by reducing the collision force between the discharge valve 13 and the valve plate 11, noise reduction can be achieved.

In the present embodiment, the O-ring used as the seal member is a butadiene / acrylonitrile copolymer, a curlorosulphonated polyethylene,
By using a rubber material having excellent heat resistance, aging resistance and abrasion resistance, such as a propylene hexafluoride / vinylidene fluoride copolymer, a further effect of improving the sealing property can be obtained. Further, since the durability is remarkably improved, high reliability can be obtained.

In this embodiment, the rubber material such as the O-ring used as the seal member is used, but a resin material may be used. In particular, resin-based materials with properties such as heat resistance, aging resistance, wear resistance, and elasticity have high sealing properties, high efficiency, and
High reliability can be obtained.

(Embodiment 2) FIG. 4 is a cross-sectional view of a main part around a discharge valve during a discharge stroke according to an embodiment of the present invention. FIG. 5 is a cross-sectional view of the main parts around the discharge valve during the intake stroke of the same embodiment.

In FIGS. 4 and 5, 19 is a discharge valve having a resin coating 19a, and 20 is a valve plate.

The operation of the linear compressor configured as described above will be described below with reference to FIGS.

The refrigerant is introduced into the closed container 1 through the suction pipe. The refrigerant introduced into the closed container 1 enters the compression chamber 8 from the suction side space 14 of the head cover part 9 through the suction valve 12 assembled to the valve plate 20. After that, it is discharged outward from the discharge valve 19 through the discharge hole 11a, the discharge side space 15 of the head cover portion 9, and the discharge pipe (not shown).

Here, looking at the behavior of the discharge valve 19 in the discharge and suction strokes during a series of reciprocating motions of the piston 4, the discharge valve 19 receives a differential pressure during the discharge stroke and is bent upward in the drawing. To do. Next, in the intake stroke, as the piston 4 moves toward the head cover portion 9 side, the force due to the pressure difference between the compression chamber 8 and the discharge side space 15 is received, the discharge valve 19 approaches the valve plate 20, and the discharge valve 19 The resin-based coating 19a of 19 is in contact with the valve plate 20 and is compressed in close contact. From the above results, the sealing property of the discharge valve 19 is improved.

Therefore, under high differential pressure and oilless conditions such as CO2 refrigerant, the sealing property of the discharge valve 19 can be remarkably improved, and the leakage loss during the intake stroke can be reduced and the efficiency can be improved. Also, the discharge valve 19 and the valve plate 2
By reducing the collision force of 0, noise can be reduced.

As described above, in the linear compressor for CO2 refrigerant of this embodiment, the discharge valve 19 is coated with the resin coating 1
9a is provided, the sealability of the discharge valve 19 can be remarkably improved, and the leakage loss during the suction stroke can be reduced to improve the efficiency. Further, by reducing the collision force between the discharge valve 19 and the valve plate 20, noise reduction can be achieved.

(Embodiment 3) FIG. 6 is a cross-sectional view of a main portion around a discharge valve in a discharge stroke according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of the main parts around the discharge valve during the suction stroke of the same embodiment.

In FIGS. 6 and 7, 21 is a discharge valve 22.
Is a spring body that is installed between the head cover 23 and the head cover 23 and presses and supports the discharge valve 22, and plays a role of assisting the opening and closing of the valve. In this embodiment, the coil spring 21a is used. Also, 24
Is the valve plate. Further, in the reference numeral 25, a concave portion 26 is provided on the valve plate 24 side of the opening / closing surface portion 16, and the concave portion 26 is provided.
It is an O-ring installed in.

The operation of the linear compressor configured as described above will be described below with reference to FIGS.

The refrigerant is introduced into the closed container 1 through the suction pipe. The refrigerant introduced into the closed container 1 enters the compression chamber 8 from the suction side space 14 of the head cover part 23 through the suction valve 12 assembled to the valve plate 24. After that, it is discharged from the discharge valve 22 through the discharge hole 11a, the discharge side space 15 of the head cover portion 23, and the discharge pipe (not shown) to the outside.

Here, looking at the behavior of the discharge valve 22 in the discharge and suction strokes during a series of reciprocating motions of the piston 4, the discharge valve 22 receives a differential pressure during the discharge stroke and moves upward (FIG. 6). At this time, the coil spring 21a installed between the discharge valve 22 and the upper end surface of the head cover 23 is compressed and contracted. Next, in the suction stroke, as the piston 4 moves in the direction opposite to the head cover portion 23 side, a force due to the pressure difference between the compression chamber 8 and the discharge side space 15 is received, and further the coil spring 21a.
The spring reaction force of
Comes closer to the valve plate 24 and presses the O-ring 25, so that the adhesion between the valve plate 24 and the discharge valve 22 is further increased (see FIG. 7).

Therefore, the sealing performance of the discharge valve 22 can be remarkably improved under a high differential pressure refrigerant such as CO2 and the oilless condition, and the leakage loss during the intake stroke can be reduced to achieve high efficiency.

Further, since the coil spring 21a is used as the spring body, the cost can be reduced.

As described above, the linear compressor for CO2 refrigerant according to the present embodiment has a structure in which the discharge valve 22 is pressed and supported by the spring body, and when the discharge valve 22 is closed, a spring force is applied to it. The sealing property of the discharge valve 22 can be significantly improved. As a result, it is possible to reduce leakage loss during the intake stroke and improve efficiency. Further, since the coil spring is used as the spring material, cost reduction can be realized.

(Embodiment 4) FIG. 8 is a cross-sectional view of essential parts around a discharge valve in a discharge stroke of a linear compressor according to Embodiment 4 of the present invention. FIG. 9 is a cross-sectional view of the main parts around the discharge valve during the intake stroke of the same embodiment.

In FIGS. 8 and 9, 27 is a leaf spring located on the opposite side of the opening / closing surface 16 of the discharge valve 28, and is supported and fixed to the valve plate 30 integrally with the discharge valve 28 by the discharge stopper 29. Further, reference numeral 31 is an O-ring which is provided with a recess 32 on the valve plate 30 side of the opening / closing surface 16 and is installed in this recess 32.

This embodiment differs from the third embodiment in that
The spring body is a leaf spring.

The operation of the linear compressor configured as described above will be described below with reference to FIGS.

The refrigerant is introduced into the closed container 1 through the suction pipe. The refrigerant introduced into the closed container 1 enters the compression chamber 8 from the suction side space 14 of the head cover 9 through the suction valve 12 assembled to the valve plate 30. After that, through the discharge hole 11a, the discharge valve 28 discharges outward from the discharge pipe (not shown) through the discharge side space 15 of the head cover 9.

Looking at the behavior of the discharge valve 28 in the discharge and suction strokes during a series of reciprocating movements of the piston 4, the discharge valve 28 receives a differential pressure during the discharge stroke, and the discharge hole 11
It deforms upward while sliding in the a direction. At this time, it is buffered by the leaf spring 27 located above and is bent and deformed together with the leaf spring (see FIG. 8). Next, in the suction stroke, as the piston 4 moves in the direction opposite to the head cover 9 side, the discharge valve 28
Receives the force due to the pressure difference between the compression chamber 8 and the discharge side space 15, and the spring reaction force of the leaf spring 27 is also added at the same time, thereby approaching the valve plate 30 and pressing the O-ring 31 to the valve plate 30. In close contact. Therefore, the adhesion of the discharge valve 28 is further increased, and the leakage loss is significantly reduced.

Therefore, the sealing performance of the discharge valve 28 can be remarkably improved under the high differential pressure refrigerant such as CO2 and the oilless condition, and the leakage loss at the intake stroke can be reduced and the efficiency can be improved.

Further, since the discharge valve 28 and the plate spring 27 are structured to open and close while sliding, the valve plate 30 is opened and closed more smoothly than the cantilever spring.
Since the valve behavior that diffuses the impact force of the valve given to the valve is performed, noise reduction can be realized.

As described above, in the linear compressor for CO2 refrigerant according to the present embodiment, the spring body is the leaf spring 27. Therefore, by adding the spring force when the discharge valve 28 is closed, The sealing performance of the discharge valve 28 can be significantly improved. As a result, it is possible to reduce leakage loss during the intake stroke and improve efficiency. Further, since the discharge valve 28 opens and closes smoothly and acts as a valve that diffuses the impact force of the valve, low noise can be realized.

In the present embodiment, the same effect can be obtained if the supporting structure in which the discharge valve 28 and the leaf spring 27 are slidably opened and closed is satisfied. Therefore, the form of the discharge stopper according to the present embodiment can be obtained. Not limited.

[0062]

As described above, according to the first aspect of the invention, since the seal member is arranged on the opening / closing surface portion of the discharge valve without using the lubricating oil, the sealing property of the discharge valve is remarkably improved. It is possible to improve the efficiency, reduce leakage loss during the intake stroke, and improve efficiency. Moreover, noise can be reduced by reducing the collision force between the discharge valve and the valve plate.

The invention described in claim 2 is the same as claim 1
In the invention described in (1) above, since the recess is provided on the valve plate side of the opening / closing surface of the discharge valve and the O-ring is formed in the recess,
It is possible to remarkably improve the sealing property of the discharge valve, reduce leakage loss during the intake stroke, and improve efficiency. Moreover, noise can be reduced by reducing the collision force between the discharge valve and the valve plate.

The invention described in claim 3 is the same as that of claim 2
In the invention described in 1., since a rubber material of butadiene / acrylonitrile copolymer, chlorosulfonated polyethylene, propylene hexafluoride / vinylidene fluoride copolymer is used as the O-ring, heat resistance, aging resistance and wear resistance are improved. Excellent in performance and further improvement in sealing performance. Further, durability is improved and high reliability can be achieved.

The invention described in claim 4 is the same as claim 1
According to the present invention, the discharge valve is coated with a resin coating, and when the discharge valve closes the discharge hole, the discharge valve contacts the valve plate while deforming and compressing the resin coating. The valve plate will be in close contact, and the sealing performance can be improved.

The invention described in claim 5 is the same as claim 1
Alternatively, in the invention of claim 2, claim 3 or claim 4, the discharge valve is pressed and supported by a spring body, and the spring force of this spring body is applied to the discharge valve to force the discharge valve. Ground to the valve plate. As a result, the degree of contact between the discharge valve and the valve plate is improved, and the effect of further improving the sealing performance is obtained.

The invention described in claim 6 is the same as claim 5
By using a leaf spring as the spring body in the invention described in (1), the sealing performance can be improved. Further, the cost can be reduced by using the coil spring.

The invention described in claim 7 is the same as claim 5
By using a leaf spring as the spring body in the invention described in (1), the sealing performance can be improved. Furthermore, since the discharge valve opens and closes smoothly and behaves as a valve that diffuses the impact force of the valve, low noise can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing an overall configuration of a linear compressor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main portion around a discharge valve during a discharge stroke of the same embodiment

FIG. 3 is a cross-sectional view of the main parts around the discharge valve during the intake stroke of the same embodiment.

FIG. 4 is a cross-sectional view of a main portion around a discharge valve during a discharge stroke of a linear compressor according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of the main parts around the discharge valve during the intake stroke of the same embodiment.

FIG. 6 is a cross-sectional view of a main portion around a discharge valve during a discharge stroke of a linear compressor according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view of the main part around the discharge valve during the intake stroke of the same embodiment.

FIG. 8 is a cross-sectional view of a main portion around a discharge valve during a discharge stroke of a linear compressor according to a fourth embodiment of the present invention.

FIG. 9 is a cross-sectional view of the main parts around the discharge valve during the intake stroke of the same embodiment.

[Explanation of symbols]

1 closed container 3 cylinders 4 pistons 6 linear motor 8 compression chambers 9,23 Head cover part 11 valve plate 11a discharge hole 13, 19, 22 Discharge valve 16 Opening / closing part 17 recess 18 Seal member 18a O-ring 19a Resin coating 21a coil spring 27 leaf spring

Claims (7)

[Claims] 1. An airtight container, a head cover portion and a cylinder formed inside the airtight container, a linear motor fixed to the cylinder, and a cylinder slidably supported along the axial direction thereof. A piston, a compression chamber provided between the piston and the head cover portion, a valve plate provided with a discharge hole for guiding discharge of CO2 refrigerant compressed in the compression chamber, and a discharge for opening and closing the discharge hole. A linear compressor for CO2 refrigerant, comprising a valve, wherein a seal member is arranged on the opening / closing surface of the discharge valve without using lubricating oil. 2. The linear compressor for CO2 refrigerant according to claim 1, wherein the seal member comprises an O-ring mounted in a recess provided on the valve plate side of the opening / closing surface of the discharge valve. 3. A butadiene-acrylonitrile copolymer, O-ring, chlorosulfonated polyethylene, 6
The linear compressor for CO2 refrigerant according to claim 2, wherein a rubber material of a propylene fluoride / vinylidene fluoride copolymer is used. 4. The linear compressor for CO2 refrigerant according to claim 1, wherein the discharge valve is resin-coated. 5. The discharge valve is pressed and supported by a spring body.
Or C according to claim 2 or claim 3 or claim 4
Linear compressor for O2 refrigerant. 6. The linear compressor for CO2 refrigerant according to claim 5, wherein the spring body is a coil spring. 7. The linear compressor for CO2 refrigerant according to claim 5, wherein the spring body is a leaf spring.