JP2005090626A - Sealing construction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing construction in which it is possible to save the space and reduce the costs, and it is possible to effectively prevent carbon dioxide gas from leaking out for a long period in usage circumference under high temperature. <P>SOLUTION: In the sealing construction, a cylinder bore in which high pressure carbon dioxide circulates is formed by jointing a cylinder block 2 and a rear housing 6 to seal the clearance between mutually adjoining cylinder block 2 and the rear housing 6. At a mutual contact surface of the cylinder block 2 and the rear housing 6, a first seal ring 50 arranged at a high pressure side near the cylinder bore 3, preventing the penetration of carbon dioxide gas, and a second seal ring arranged at a low pressure side outside the first seal member 50, preventing the permeation of oxygen is formed to intervene. This makes it possible to prevent the leakage of carbon dioxide gas with the first seal member 50, and to prevent the permeation of oxygen with the second seal ring 51. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a seal structure that seals a gas circulation space in which high-pressure carbon dioxide gas circulates. For example, the present invention is suitable for application to a seal structure between divided housings of an air conditioner.

Recently, from the viewpoint of environmental problems in the air conditioner of an automobile, instead chlorofluorocarbon that has been used until then as a refrigerant, C0 2 _(carbon dioxide, hereinafter, simply referred to as carbon dioxide) have been the shifts in the direction the refrigerant .

  When this carbon dioxide gas is used as the refrigerant, the pressure in the compressor of the air conditioner is much higher than the pressure (about 3 [MPa]) when using chlorofluorocarbon as the refrigerant (about 11 [MPa]). Tend to be. Further, this carbon dioxide gas is more soluble and more permeable to organic substances such as polymers and rubbers than fluorocarbon.

  For this reason, various devices for using carbon dioxide gas as a refrigerant have been made. For example, as shown in FIG. 5, on the joint surface between the cylinder block 71 and the rear housing 72 of the compressor, That is, a seal structure is disclosed in which an O-ring 73 made of nitrile rubber is provided on the high pressure side, and a gasket 74 is provided on the outside, that is, on the low pressure side, with a metal plate 74b sandwiched by a nitrile rubber plate 74a (for example, , See Patent Document 1).

  The above seal structure uses an O-ring with high pressure resistance and is sealed twice with nitrile rubber that can effectively prevent the permeation of carbon dioxide, so carbon dioxide is sealed at high pressure and sealed at high pressure. The carbon dioxide gas can be sealed so that it does not leak outside as much as possible.

By the way, since the carbon dioxide gas in the compressor becomes a high pressure (about 11 [MPa]) and a high temperature (about 140 ° C.), the seal structure has carbon dioxide gas in a high temperature (about 140 ° C.) environment for a long time. It is required that external leakage can be prevented.
JP 2002-317764 A (page 3 and page 4, FIG. 1 and FIG. 2)

  However, both the O-ring 73 and the rubber plate 74a of the cascade 74 are nitrile rubber, and the nitrile rubber is hardened by oxidative degradation in a high temperature environment (about 140 ° C.), so that the carbon dioxide gas leaks out for a long time. There is a problem that cannot be prevented.

  Examples of rubber materials that can be used for a long time in a high temperature (about 140 ° C.) environment include fluoro rubber (FKM) and silicon rubber. However, fluororubber is foamed by carbon dioxide gas, and there is a problem in permeation-preventing property of carbon dioxide gas as well as durability. Further, silicon rubber has a problem that the permeation-preventing property of carbon dioxide gas is too bad and is weak in strength.

  Thus, even if the sealing material has a double structure and a rubber material having excellent heat resistance is used as the material of the sealing material, in a use environment under a high temperature (140 ° C. or higher), it will last for a long time. It is impossible to effectively prevent carbon dioxide from leaking outside.

  Further, in this seal structure, the gasket 74 that uses a plate-shaped wide space together with the O-ring 73 is disposed on the same surface, which is a joint surface between the cylinder block 71 and the rear housing 72, so that there is a problem that the space efficiency is poor.

  Furthermore, since the expensive plate-shaped gasket 74 is used compared with seal rings, such as O-ring 73, there exists a problem that cost becomes high.

  Therefore, the present invention has been made in view of such circumstances, and can save space and cost, and can effectively prevent external leakage of carbon dioxide gas over a long period of time in a high-temperature use environment. An object of the present invention is to provide a seal structure that can be prevented.

  In order to achieve the above object, the invention according to claim 1 is a seal structure in which a gas circulation space in which high-pressure carbon dioxide gas circulates is formed by joining a plurality of outer wall members to seal between the adjacent outer wall members. In addition, between the joint surfaces of the outer wall members, a first seal ring that is disposed on the high pressure side near the gas circulation space and prevents permeation of carbon dioxide gas, and a low pressure outside the first seal ring. A second seal ring that is disposed on the side and prevents permeation of oxygen is interposed.

  The invention according to claim 2 is the seal structure according to claim 1, wherein the first seal ring is an O-ring made of an annular rubber material.

  The invention of claim 3 is the seal structure according to claim 1 or claim 2, wherein the second seal ring is a seal ring having a notch at one annular position.

  A fourth aspect of the present invention is the seal structure according to the first to third aspects, wherein each outer wall member is a member forming a housing of a compressor.

  In the first aspect of the invention, the first seal ring prevents internal carbon dioxide gas from leaking outside through the gap between adjacent outer wall members, while external oxygen enters the inside through the gap between adjacent outer wall members. The second seal ring prevents the carbon dioxide gas from leaking outside, and the heat resistance can be greatly improved by suppressing the hardening due to oxidative degradation of the first seal ring.

  In addition, according to the present invention, since the seal ring, which may have a smaller seal area compared to the plate-like gasket, is installed and sealed, the space efficiency of the seal structure is good. Furthermore, according to the present invention, since only an inexpensive seal ring is used as compared with a gasket having a plate-like laminated structure, the cost can be reduced.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the first seal ring is an O-ring, so that the diameter of the annular first seal ring is extended to slightly increase the joint surface. Since it is only necessary to mount by being inserted into the seal groove, the mounting operation can be easily performed.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1 or claim 2, the second seal ring has a notch at one location, so the second seal ring is heated. Without being inserted into the sealing groove on the joint surface, and the mounting operation can be simplified. In other words, if the resin-made second seal ring is an annular O-ring, it is necessary to make the second seal ring flexible by heating and install it in the seal groove. There is no need for such troublesome work.

  According to the fourth aspect of the present invention, when this seal structure is used for a compressor that compresses high-pressure carbon dioxide gas in particular, leakage of the high-pressure gas can be suppressed over a long period of time.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 to 4 show a case where the seal structure of the present invention is applied to a compressor A, FIG. 1 is a sectional view of the compressor A, FIG. 2 is an enlarged sectional view of the seal structure, and FIG. FIG. 3B is a perspective view of a modified example of the second seal ring, and FIG. 4 is a diagram showing changes in heat resistance of various rubber materials in an air atmosphere and a carbon dioxide atmosphere.

In Figure 1, the compressor A is used in the cooling system of an air conditioner for a vehicle, the cooling system C0 2 _(carbon dioxide, hereinafter, simply referred to as carbon dioxide gas) to the refrigerant gas. The high-temperature and high-pressure carbon dioxide gas adiabatically compressed by the compressor A is liquefied by a condenser (condenser) (not shown), adiabatically expanded by an expansion valve, heated and vaporized while producing cold air by an evaporator (evaporator), It returns to the compressor A and is adiabatically compressed.

  The housing 1 of the compressor A is mainly configured by connecting a cylinder block 2, a front housing 4, and a rear housing 6, which are a plurality of outer wall members.

  A plurality of cylinder bores 3 which are gas circulation spaces are formed in the cylinder block 2 in the circumferential direction, and carbon dioxide gas is adiabatically compressed in the cylinder bore 3. A crank chamber 5 is formed in the front housing 4, and the crank chamber 5 and the cylinder bore 3 are partitioned by a piston 18 described below. A refrigerant suction chamber 7 and a refrigerant discharge chamber 8 are formed in the rear housing 6. A suction plate 30, a valve plate 9, a discharge plate 31, a retainer 32, and a gasket 33 are interposed between the rear housing 6 and the cylinder block 2, and thereby, the refrigerant suction chamber 7, the refrigerant discharge chamber 8, the cylinder bore 3, and the like. Is partitioned.

  The refrigerant suction chamber 7 is connected to the evaporator side via the refrigerant flow path, and the refrigerant discharge chamber 8 is connected to the condenser side via the refrigerant flow path.

  Inside the crank chamber 5, a drive plate 11 fixed to the drive shaft 10, a sleeve 12 that is loosely fitted to the outer periphery of the drive shaft 10, and a sleeve 13 that is swingably connected by a pin 13. A journal 14 and a swash plate 15 screwed around the outer periphery of the journal 14 are accommodated.

  The journal 14 is connected to the long hole 16 of the drive plate 11 by a pin 17, and the swing angle of the journal 14 (swash plate 15) is regulated by the long hole 16.

  The piston 18 fitted to each cylinder bore 3 is connected to the swash plate 15 via a pair of piston shoes 19, 19 with the swash plate 15 interposed therebetween. The piston 18 is prevented from rotating with respect to the cylinder bore 3 by a rotation preventing portion 18 a formed in contact with the peripheral surface of the crank chamber 5.

  Further, a pulley 20 is supported on the left end portion of the front housing 4 via a bearing 21. A first drive transmission plate 22 is screwed to the inner periphery of the pulley 20, and a second drive transmission plate 23 is fixed to the tip of the drive shaft 10.

  These plates 22 and 23 are slidably coupled with a driving torque equal to or higher than a set value, and transmit the rotation of the pulley 20 to the drive shaft 10.

  Pressure adjusting means 40 is disposed in the rear housing 6, and this pressure adjusting means 40 adjusts the differential pressure between the refrigerant suction chamber 7 and the crank chamber 5 on the evaporator side.

  The inclination angle of the swash plate 15 is changed by adjusting the differential pressure between the refrigerant suction chamber 7 and the crank chamber 5 by the pressure adjusting means 40, and the stroke of each piston 18 is changed along with the change in the inclination angle, so that carbon dioxide, which is a refrigerant gas. The gas discharge amount is controlled.

  Further, as shown in detail in FIG. 2, a first seal ring 50 and a second seal ring 51 are doubly interposed on the joint surface between the cylinder block 2 and the rear housing 6, and thereby the cylinder block 2. And the rear housing 6 are sealed.

  The first seal ring 50 is fitted in a seal groove 50 a close to the cylinder bore 3 side of the cylinder block 2, and the second seal ring 51 is fitted in a seal groove 50 b located outside the first seal ring 50. Has been. That is, the first seal ring 50 is disposed on the high pressure side on the cylinder bore 3 side, and the second seal ring 51 is disposed on the low pressure side on the atmosphere side.

  The first seal ring 50 is made of a rubber material that prevents permeation of carbon dioxide gas, and is composed of an annular O-ring. Specific materials include butyl rubber (IIR), chlorinated polyerylene (CPE), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), ethylene / propylene / diene rubber (EPDM), and the like.

  The second seal ring 51 is made of a resin material that prevents the permeation of oxygen, and as shown in FIG. 3A, the second seal ring 51 is constituted by a seal ring having a notch at one annular position. Specific resin materials are ethylene / vinyl acetate copolymer resin (EVA), fluororesin (PTFE), nylon (registered trademark), polyethylene terephthalate (PET), and the like.

  The cut surface 51a in the notch of the second seal ring 51 is set in an oblique direction, and in a state of being sandwiched between the cylinder block 2 and the rear housing 6, the cut surfaces are in close contact with each other, In addition, air does not leak from the gap. FIG. 3B shows a modified example of the second seal ring 51. In this modified example, the cut surface 51b is set in a stepped shape, and the cylinder block 2 and the rear housing 6 are similar to the above. In a state of being sandwiched between them, the cut surfaces are in close contact with each other, and air does not leak from the gap.

  In the above configuration, when the compressor A is driven, the piston 18 slides in the cylinder bore 3, and by this sliding, the carbon dioxide gas in the refrigerant suction chamber 7 is sucked into the cylinder bore 3 and the sucked carbon dioxide gas is compressed. Then, the refrigerant is discharged into the refrigerant discharge chamber 8. That is, in the cylinder bore 3, carbon dioxide gas is discharged to the refrigerant discharge chamber 8 as a high temperature and high pressure by adiabatic compression, so that the inside of the cylinder bore 3 is high pressure (about 11 [MPa]) and high temperature (about 140 ° C.).

  Here, as shown in FIG. 2, the first seal ring 50 prevents internal carbon dioxide gas from leaking outside through the gap between the cylinder block 2 and the rear housing 6, while oxygen in the outside air is The second seal ring 51 prevents intrusion from the inside. In particular, since the second seal ring 51 is formed of a material suitable for preventing oxygen from entering, the second seal ring 51 can prevent the first seal ring 50 from being exposed to oxygen. Oxidative deterioration of the first seal ring 50 can be suppressed. As a result, the durability of the first seal ring 50 can be greatly improved.

  Further, as shown in FIG. 4, the rubber material used for the first seal ring 50 has heat resistance that does not deteriorate the sealing performance under a high temperature environment (about 140 ° C.) in a carbon dioxide gas atmosphere. Therefore, carbon dioxide gas can be effectively prevented from leaking over a long period of time in a use environment at a high temperature (about 140 ° C.). Further, as shown in FIG. 4, since a plurality of rubber materials can be used for the first seal ring 50, the selection range of the applicable rubber material is improved, which contributes to cost reduction.

  In addition, according to the seal structure of the present embodiment, since the seal rings 50 and 51 that may have a smaller seal area than the conventional plate-like gasket are installed and sealed, the space efficiency of the seal structure is improved. Is good.

  Furthermore, according to the seal structure of the present embodiment, since only the seal rings 50 and 51 that are less expensive than the conventional gasket having the plate-like laminated structure are used, the cost can be reduced.

  In this embodiment, since the first seal ring 50 is an O-ring made of an annular rubber material, the first seal ring 50 is extended to slightly increase the diameter of the annular first seal ring 50, and is formed in the sealing groove 50a on the joint surface. Since it only has to be mounted by fitting, the mounting work can be facilitated.

  In this embodiment, the second seal ring 51 is a seal ring having a notch at one annular position, so that the second seal ring 51 can be fitted into the sealing groove 50b on the joint surface without heating. The installation work is not troublesome. That is, if the resin-made second seal ring 51 is an annular O-ring, the second seal ring 51 needs to be heated and flexible to be mounted in the sealing groove 50b. There is no need for such troublesome work.

In the present embodiment, the present invention is applied to the seal structure of the housing 1 of the compressor A. However, the present invention can be similarly applied to a joint portion of the refrigerant path of the refrigerant cycle.

1 is a cross-sectional view of a compressor according to an embodiment of the present invention. 1 shows an embodiment of the present invention and is an enlarged sectional view of a seal structure. FIG. FIG. 5A is a perspective view of a second seal ring, and FIG. 5B is a perspective view of a modification of the second seal ring according to an embodiment of the present invention. It is a figure which shows one Embodiment of this invention and shows the heat resistance change in the air atmosphere and carbon dioxide gas atmosphere of various rubber materials. It is sectional drawing of the seal structure of a prior art example.

Explanation of symbols

A Compressor 2 Cylinder block (outer wall member)
3 Cylinder bore (gas distribution space)
6 Rear housing (outer wall member)
50 First seal ring 51 Second seal ring

Claims (4)

A gas flow space (3) through which high-pressure carbon dioxide gas flows is formed by joining a plurality of outer wall members (2) and (6), and a seal that seals between the adjacent outer wall members (2) and (6) Structure,
Between the joint surfaces of the outer wall members (2) and (6), a first seal ring (50) disposed on the high pressure side near the gas circulation space (3) and preventing permeation of carbon dioxide gas, A seal structure characterized in that a second seal ring (51) is disposed on the low pressure side outside the first seal ring (50) and prevents permeation of oxygen. The seal structure according to claim 1,
The first seal ring (50) is an O-ring made of an annular rubber material. A seal structure according to claim 1 or claim 2,
The second seal ring (51) is a seal ring having a cutout at one annular position. The seal structure according to claim 1, wherein
Each said outer wall member (2), (6) is a member which forms the housing (1) of a compressor (A). The sealing structure characterized by the above-mentioned.

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