Scroll compressor

Abstract

There is provided a scroll compressor comprising: a fixed-side member comprising a casing and a fixed scroll member provided in the casing; a driving shaft rotatably provided in the casing; an orbiting scroll member orbitably provided at a distal end of the driving shaft; a suction opening provided in the fixed-side member; and a discharge opening provided in the fixed-side member. Each of the scroll members includes an end plate and a spiral wrap portion standing on the end plate. The wrap portion of the orbiting scroll member is adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers. The suction opening communicates with the outermost compression chamber, and the discharge opening is adapted to discharge a compressed gas from an inner compression chamber. A seal member comprising an elastic member is provided around an outer circumferential surface of the orbiting scroll member, so as to seal the compression chambers relative to outside air between the orbiting scroll member and the fixed-side member. The seal member has an opening on a radially inner side thereof and has a generally U-shaped cross-section.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a scroll compressor which is used to compress a gas. More specifically, the present invention relates to a scroll compressor which is advantageously used for a booster connected to a city gas supply pipe to increase the pressure of a gas.

Generally, a scroll compressor comprises a casing, a fixed scroll member provided in the casing, which includes an end plate and a spiral wrap portion standing on the end plate, a driving shaft rotatably provided in the casing, and an orbiting scroll member orbitably provided at a distal end of the driving shaft, which orbiting scroll member is adapted to transfer a compressed gas from a suction opening to a discharge opening. The orbiting scroll member includes an end plate and a spiral wrap portion standing on the end plate. The wrap portion of the orbiting scroll member is adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers.

In the scroll compressor of this type, the orbiting scroll member is subject to an orbital motion, with a predetermined orbiting radius (or eccentric distance) about the center axis of the fixed scroll member. Thus, a gas sucked in from the suction opening provided at an outer periphery of the fixed scroll member is compressed in each compression chamber between the wrap portions of the fixed and orbiting scroll members, and discharged to the outside through the discharge opening provided at a central portion of the fixed scroll member.

When the above-mentioned scroll compressor is applied to compressing a refrigerant for air conditioning or a cooling operation, since the pressure of the refrigerant (in gaseous form) at the suction opening is higher than atmospheric pressure, a problem arises, such that the refrigerant at the suction opening is likely to escape to the outside through a space between the outer peripheries of the fixed scroll member and the orbiting scroll member. Therefore, as a refrigerant compressor in the related art, a closed-type compressor has been employed, in which the main body of the compressor is confined in a container, together with an electric motor for rotating the driving shaft.

In a closed-type compressor, the inside of the container is shielded from outside air. Therefore, in order to cool the compressor which is heated during operation, a cooling method using a gas to be compressed by the compressor or a cooling method using a lubricant is required to be used.

When a closed-type compressor is used as a refrigerant compressor, it has no cooling problem. However, when it is applied to compressing a gas having a low heat capacity, such as a city gas, a cooling ability of the gas is insufficient, so that the compressor cannot be cooled to a satisfactory level.

On the other hand, in a cooling method using a lubricant, it is difficult to separate a compressed gas and the lubricant. This makes it difficult to apply the compressor to, for example, a city gas booster. Further, this method cannot be employed in an oilless-type compressor using no lubricant.

When an oilless-type compressor exposed to outside air is applied to compressing a high-pressure gas such as that in a city gas supply pipe, the gas leaks from the suction opening to the outside.

SUMMARY OF THE INVENTION

The present invention has been made, in view of the above-mentioned problems accompanying the related art. It is an object of the present invention to provide a scroll compressor which prevents leakage of a gas even when a gas having a pressure higher than atmospheric pressure is compressed.

The present invention provides a scroll compressor comprising:

a fixed-side member comprising a casing and a fixed scroll member provided in the casing, the fixed scroll member including an end plate and a spiral wrap portion standing on the end plate;

a driving shaft rotatably provided in the casing;

an orbiting scroll member orbitably provided at a distal end of the driving shaft, the orbiting scroll member including an end plate and a spiral wrap portion standing on the end plate, the wrap portion of the orbiting scroll member being adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers;

a suction opening provided in the fixed-side member so as to communicate with the outermost compression chamber of the plurality of compression chambers;

a discharge opening provided in the fixed-side member so as to discharge a compressed gas from an inner compression chamber of the plurality of compression chambers to the outside; and

a seal member comprising an elastic member provided around an outer circumferential surface of the orbiting scroll member, so as to seal the plurality of compression chambers relative to outside air between the orbiting scroll member and the fixed-side member, the seal member having an opening on a radially inner side thereof and having a generally U-shaped cross-section.

The present invention also provides a scroll compressor comprising:

a casing;

a fixed scroll member provided in the casing, the fixed scroll member including an end plate and a spiral wrap portion standing on the end plate;

a driving shaft rotatably provided in the casing;

an orbiting scroll member orbitably provided at a distal end of the driving shaft, the orbiting scroll member including an end plate and a spiral wrap portion standing on the end plate, the wrap portion of the orbiting scroll member being adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers;

a suction opening communicated with the outermost compression chamber of the plurality of compression chambers;

a discharge opening adapted to discharge a compressed gas from an inner compression chamber of the plurality of compression chambers to the outside; and

a seal apparatus provided on an outer circumferential surface of the orbiting scroll member, so as to seal the plurality of compression chambers relative to outside air between the orbiting scroll member and the fixed scroll member,

the seal apparatus comprising:

a grooved, annular seal mounting member having an opening, the annular seal mounting member being attached to the outer circumferential surface of the orbiting scroll member so that the opening of the groove faces the fixed scroll member; and

a ring-shaped seal member for providing an gas-tight seal between the fixed scroll member and the orbiting scroll member, the seal member being attached to the groove of the annular seal mounting member so as to allow a part of the gas to flow into the inside of the seal member and increase sealing performance of the seal member.

The foregoing and other objects, features and advantages of the present invention will be apparent from the following detailed description and appended claims taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view of a scroll gas compressor according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a portion a in FIG. 1 .

FIG. 3 is a vertical cross-sectional view of a scroll gas compressor according to a second embodiment of the present invention.

FIG. 4 is an enlarged view of a portion b in FIG. 3 .

FIG. 5 is an enlarged, vertical cross-sectional view of a contact seal and its vicinities of a scroll gas compressor according to a third embodiment of the present invention.

FIG. 6 is an enlarged view of a portion c in FIG. 5 .

FIG. 7 is a cross-sectional view of a contact seal shown in FIG. 6 alone.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, referring to the accompanying drawings, description is made in detail with regard to a scroll compressor according to embodiments of the present invention, in which a scroll gas compressor connected to a city gas supply pipe is taken as an example.

FIGS. 1 and 2 show a first embodiment of the present invention. Reference numeral 1 denotes a casing providing an outer frame of a scroll gas compressor. The casing 1 and a fixed scroll member 2 (described below) provide a fixed-side member. The casing 1 is in a stepped cylindrical form and comprises a large-diameter portion 1 A and a small-diameter portion 1 B.

The fixed scroll member 2 is fixed to the large-diameter portion 1 A of the casing 1 . The fixed scroll member 2 generally comprises: an end plate 2 A in the form of a circular plate disposed in a coaxial relationship to a driving shaft 3 (described later); a spiral wrap portion 2 B standing on an obverse side of the end plate 2 A; an outer edge portion 2 C disposed radially outward of the end plate 2 A so as to surround the wrap portion 2 B; and a ring-receiving portion 2 D in a platy form extending vertically from the outer edge portion 2 C toward the center axis of the end plate 2 A. A number of radiating fins 2 E are provided on a rear side of the end plate 2 A. The outer edge portion 2 C of the fixed scroll member 2 is connected integrally to a distal end of the large-diameter portion 1 A of the casing 1 .

A crank 3 A is provided so as to project from a distal end of the driving shaft 3 . The driving shaft 3 is rotatably supported through bearings 3 B and 3 C in the small-diameter portion 1 B of the casing 1 . The driving shaft 3 has a pulley 29 (described later) attached to a proximal end thereof and rotates on its axis. The axis of the crank 3 A is displaced from the axis of the driving shaft 3 by a predetermined distance.

Reference numeral 4 denotes a balance weight fixed to the distal end of the driving shaft 3 . The balance weight 4 is used to obtain a rotational balance of the driving shaft 3 relative to an orbital motion of an orbiting scroll member 5 described later.

The orbiting scroll member 5 is orbitably provided in the casing 1 so as to face the fixed scroll member 2 . The orbiting scroll member 5 comprises an orbiting scroll main body 6 and a rear plate 7 . The orbiting scroll member 5 is orbitably supported on the crank 3 A using an orbiting bearing 9 (described later).

The orbiting scroll main body 6 has substantially the same structure as the fixed scroll member 2 and comprises an end plate 6 A and a spiral wrap portion 6 B. A number of radiating fins 6 C are provided on the end plate 6 A. The orbiting scroll member 5 is disposed in a manner such that the wrap portion 6 B overlap the wrap portion 2 B of the fixed scroll member 2 with a predetermined offset angle of, for example, 180° C., to thereby form a plurality of compression chambers 8 between the wrap portion 2 B and the wrap portion 6 B.

The rear plate 7 is fixed to distal ends of the radiating fins 6 C of the orbiting scroll main body 6 . A central portion of the rear plate 7 is integrally formed with a boss portion 7 A.

The orbiting bearing 9 is provided in the boss portion 7 A of the rear plate 7 so as to receive the crank 3 A of the driving shaft 3 . Thus, the orbiting bearing 9 supports the orbiting scroll member 5 relative to the crank 3 A of the driving shaft 3 , in a manner such that the orbiting scroll member 5 can be subject to an orbital motion.

Reference numeral 10 denotes a plurality of auxiliary cranks (only one auxiliary crank 10 is shown in FIG. 1 ) provided between the casing 1 and the rear plate 7 of the orbiting scroll member 5 . Each auxiliary crank 10 is adapted to prevent the orbiting scroll member 5 from rotating on its own axis when the orbiting scroll member 5 is subject to an orbital motion.

Reference numeral 11 denotes two suction openings formed at an outer periphery of the fixed scroll member 2 . Each suction opening 11 is open to a suction chamber 12 defined at the outer periphery of the fixed scroll member 2 . Each suction opening 11 is connected to a supply pipe 14 (described later). The suction chamber 12 is communicated with the outermost compression chamber 8 of the above-mentioned compression chambers 8 . Thus, during operation of the compressor, a gas supplied from the supply pipe 14 flows through the suction openings 11 and the suction chamber 12 into the outermost compression chamber 8 .

Reference numeral 13 denotes a discharge opening formed at a central portion of the end plate 2 A of the fixed scroll member 2 . The discharge opening 13 is open to the innermost compression chamber 8 so as to discharge a compressed gas to the outside.

The supply pipe 14 has a U-shaped configuration. The supply pipe 14 includes a centrally located inlet pipe 14 A and two outlet pipes 14 B branched off from the inlet pipe 14 A. A distal end of each outlet pipe 14 B forms a flange 14 C connected to each suction opening 11 of the fixed scroll member 2 . The supply pipe 14 is adapted to supply a gas, which has flowed through a suction pressure adjusting valve 15 provided at the inlet pipe 14 A, to the suction chamber 12 through the suction openings 11 .

Reference numeral 24 denotes an annular seal mounting member having a generally U-shaped cross-section. The seal mounting member 24 is formed from, for example, a metallic material. As shown in FIG. 2 , the seal mounting member 24 is press fitted over an outer circumferential surface of the orbiting scroll main body 6 , and used for mounting of a contact seal 25 (described later). The seal mounting member 24 is provided on the outer circumferential surface of the end plate 6 A so as to surround the orbiting scroll main body 6 . The seal mounting member 24 includes a seal mounting groove 24 A having a distal end thereof open toward the ring-receiving portion 2 D of the fixed scroll member 2 . The seal mounting groove 24 A provides an annular groove having an opening facing the fixed scroll member 2 .

The contact seal 25 is provided as a seal member attached to the seal mounting groove 24 A of the seal mounting member 24 . The contact seal 25 comprises a ring-shaped body seamlessly extending in a circumferential direction so as to provide an gas-tight seal between the fixed scroll member 2 and the orbiting scroll member 5 .

The contact seal 25 comprises a seal ring 26 and a spring member 27 . The seal ring 26 , which is made of a resin material, is provided as an elastic member having an opening on a radially inner side thereof and having a generally U-shaped cross-section. The spring member 27 is provided on an inner circumferential surface of the seal ring 26 .

The seal ring 26 comprises: a fixed-side annular plate portion 26 A provided at the bottom of the seal mounting groove 24 A of the seal mounting member 24 ; a sliding-side annular plate portion 26 B provided at the opening of the seal mounting groove 24 A; and a connecting cylindrical portion 26 C connecting a radially outer end of the annular plate portion 26 A and a radially outer end of the annular plate portion 26 B.

The annular plate portion 26 A of the seal ring 26 includes a fixed lip portion 26 A 1 formed at a radially inner end thereof. The fixed lip portion 26 A 1 is fittingly contained in the seal mounting groove 24 A and maintained in contact with the bottom of the groove. The annular plate portion 26 B includes a sliding lip portion 26 B 1 formed at a radially inner end thereof.

The sliding lip portion 26 B 1 projects from the seal mounting groove 24 A and is adapted to be slidably moved relative to a slidable contact ring 28 (described later) provided in the fixed scroll member 2 .

The spring member 27 is made of a metallic material (such as stainless steel) and has a generally U-shaped cross-section. The spring member 27 is fittingly connected between the annular plate portion 26 A and the annular plate portion 26 B, to thereby press the annular plate portion 26 A and the annular plate portion 26 B in opposite directions and resiliently press the fixed lip portion 26 A 1 and the sliding lip portion 26 B 1 against the seal mounting groove 24 A and the slidable contact ring 28 , respectively.

The slidable contact ring 28 is provided in the ring-receiving portion 2 D of the fixed scroll member 2 . It comprises a flat ring-shaped body made of a metallic material such as stainless steel. The slidable contact ring 28 is provided between the ring-receiving portion 2 D and the end plate 6 A of the orbiting scroll member 5 . The sliding lip portion 26 B 1 of the contact seal 25 makes slidable contact with the slidable contact ring 28 .

The pulley 29 is connected integrally to the proximal end of the driving shaft 3 by means of a bolt 30 . Reference numeral 31 denotes a centrifugal fan connected to the pulley 29 . The centrifugal fan 31 is accommodated in a fan casing 32 connected to the small-diameter portion 1 B of the casing 1 .

The scroll gas compressor in this embodiment is operated in a manner such as mentioned below.

That is, when the driving shaft 3 is rotated by an electric motor (not shown), the orbiting scroll member 5 is subject to an orbital motion with a predetermined orbiting radius about the driving shaft 3 . Consequently, the compression chambers 8 defined between the wrap portion 2 B of the fixed scroll member 2 and the wrap portion 6 B of the orbiting scroll member 5 are continuously contracted. Thus, a gas sucked in from the suction openings 11 of the fixed scroll member 2 is compressed in each compression chamber 8 and discharged through the discharge opening 13 of the fixed scroll member 2 to the outside.

When the compressor is stopped, a pressure in the suction openings 11 is maintained at about atmospheric pressure which is higher than a predetermined value.

In this embodiment, leakage of a gas can be prevented by the contact seal 25 . Therefore, differing from the above-mentioned related art, it is not required to accommodate the compressor as a whole in a closed container. Therefore, the number of parts and cost of production can be reduced. Further, the compressor can be easily cooled using various types of cooling means.

The contact seal 25 is provided around the outer circumferential surface of the orbiting scroll member 5 so as to prevent communication between the compression chambers 8 and the outside through a space between the orbiting scroll member 5 and the fixed scroll member 2 . Thus, the contact seal 25 provides a seal between the orbiting scroll member 5 and the fixed scroll member 2 and prevents a gas supplied from the suction openings 11 from leaking through the space between the orbiting scroll member 5 and the fixed scroll member 2 .

Especially, in this embodiment, the seal mounting groove 24 A having an opening facing the fixed scroll member 2 is provided in the orbiting scroll member 5 , and the contact seal 25 comprising the seal ring 26 and the spring member 27 is attached to the seal mounting groove 24 A. Therefore, the fixed lip portion 26 A 1 of the seal ring 26 is pressed against the bottom of the seal mounting groove 24 A by means of the spring member 27 , and the sliding lip portion 26 B 1 is brought into slidable contact with the fixed scroll member 2 while it is biased toward the fixed scroll member 2 by the spring member 27 . Consequently, the space between the fixed scroll member 2 and the orbiting scroll member 5 can be reliably sealed, thus preventing leakage of a gas from the suction chamber 12 through the space between the fixed scroll member 2 and the orbiting scroll member 5 to the outside. That is, by means of the sliding lip portion 26 B 1 , it is possible to prevent leakage of a gas to the outside through the space between the end plate 6 A of the orbiting scroll main body 6 and the ring-receiving portion 2 D, the space between the orbiting scroll main body 6 and the slidable contact ring 28 and the space between the seal mounting member 24 and the slidable contact ring 28 .

Further, a part of the gas prevented from leaking to the outside by the sliding lip portion 26 B 1 flows through a space between the seal mounting groove 24 A of the seal mounting member 24 and the seal ring 26 . Namely, a part of the gas flows through a space between an inner peripheral wall surface of the seal mounting groove 24 A and the radially inner end of the annular plate portion 26 B (i.e., an end of the annular plate portion 26 B on a side of the orbiting scroll main body 6 ), and is taken into the spring member 27 having a U-shaped cross-section, thus increasing a pressure of the gas inside the spring member 27 . Consequently, the fixed lip portion 26 A 1 of the seal ring 26 is pressed with a large force against the bottom of the seal mounting groove 24 A while the sliding lip portion 26 B 1 is pressed with a large force against the fixed scroll member 2 , due to the effect of spring resiliency of the spring member 27 and the pressure of the gas inside the spring member 27 . Therefore, leakage of a gas to the outside can be more reliably prevented.

FIGS. 3 and 4 show a second embodiment of the present invention. The second embodiment is characterized in that an annular partition wall member is provided in the fixed-side member so as to surround the seal mounting member provided on the outer circumferential surface of the orbiting scroll member, an intermediate chamber is formed between the partition wall member and the seal mounting member so as to accommodate a gas which has leaked through the contact seal, an auxiliary seal means is provided so as to enable the gas which has leaked into the intermediate chamber to be sealably contained in the intermediate chamber, and an escape pipe is provided so as to allow an escape of the gas from the intermediate chamber to the outside. The second embodiment is also characterized in that a gas is positively taken into the inside of the seal mounting member.

In the second embodiment, the same portions or elements as used in the first embodiment are designated by the same reference numerals and characters, and an overlapping explanation is omitted.

Reference numeral 41 denotes a fixed scroll member according to this embodiment. The fixed scroll member 41 has substantially the same structure as the fixed scroll member 2 in the first embodiment and comprises an end plate 41 A in the form of a circular plate, a wrap portion 41 B standing on the end plate 41 A, an outer edge portion 41 C disposed radially outward of the end plate 41 A, a ring-receiving portion 41 D formed on an inner circumferential side of the outer edge portion 41 C and radiating fins 41 E provided on a rear surface of the end plate 41 A. The ring-receiving portion 41 D of the fixed scroll member 41 is cut to form an annular recess 41 D 1 having a generally L-shaped cross-section.

Reference numeral 42 denotes an orbiting scroll member according to this embodiment, which is orbitably provided in the casing 1 so as to face the fixed scroll member 41 . The orbiting scroll member 42 has substantially the same structure as the orbiting scroll member 5 in the first embodiment and comprises an orbiting scroll main body 43 and a rear plate 44 .

The orbiting scroll main body 43 comprises an end plate 43 A, a wrap portion 43 B and radiating fins 43 C. An annular stepped portion 43 D is formed in an outer circumferential surface of the end plate 43 A for mounting of a seal mounting member 47 (described later). A boss portion 44 A is formed in the rear plate 44 .

Reference numeral 45 denotes a supply pipe used in this embodiment. The supply pipe 45 includes an inlet pipe 45 A and two outlet pipes 45 B branched off from the inlet pipe 45 A. A distal end of each outlet pipe 45 B forms a flange 45 C connected to each suction opening 11 of the fixed scroll member 41 . The suction pressure adjusting valve 15 (not shown) used in the first embodiment is also provided in the inlet pipe 45 A of the supply pipe 45 in this embodiment. Reference numeral 46 denotes a discharge pipe provided at the discharge opening 13 .

The inner seal mounting member 47 is provided on the outer circumferential surface of the orbiting scroll member 42 . The seal mounting member 47 is made of a metallic material and comprises an annular body having a U-shaped cross-section. The seal mounting member 47 is press fitted over the annular stepped portion 43 D of the orbiting scroll member 42 .

The seal mounting member 47 includes a seal mounting groove 47 A. The seal mounting groove 47 A has an opening on an obverse side of the seal mounting member 47 facing the ring-receiving portion 41 D of the fixed scroll member 41 . A rear side of the seal mounting member 47 provides a slidable contact surface 47 B facing a face seal 55 described later.

Reference numeral 48 denotes a contact seal used as a seal member in this embodiment, which is provided in the seal mounting groove 47 A of the seal mounting member 47 . The contact seal 48 is arranged in substantially the same manner as the contact seal 25 in the first embodiment. It is made of a resin material and comprises a seal ring 49 having an opening on a radially inner side thereof and having a generally U-shaped cross-section, and a spring member 50 provided on an inner circumferential surface of the seal ring 49 .

The seal ring 49 comprises: a fixed-side annular plate portion 49 A provided at the bottom of the seal mounting groove 47 A of the seal mounting member 47 ; a sliding-side annular plate portion 49 B provided at the opening of the seal mounting groove 47 A; and a connecting cylindrical portion 49 C connecting the annular plate portion 49 A and the annular plate portion 49 B.

The annular plate portion 49 A of the seal ring 49 includes a fixed lip portion 49 A 1 formed therein. The fixed lip portion 49 A 1 is fittingly contained in the seal mounting groove 47 A and maintained in contact with the bottom of the seal mounting groove 47 A. The annular plate portion 49 B includes a sliding lip portion 49 B 1 formed therein. The sliding lip portion 49 B 1 projects from the seal mounting groove 47 A and is adapted to be slidably moved relative to a slidable contact ring 51 provided in the annular recess 41 D 1 of the fixed scroll member 41 .

The spring member 50 is made of a metallic material and has a generally U-shaped cross-section. The spring member 50 is fittingly connected between the annular plate portion 49 A and the annular plate portion 49 B, to thereby press the annular plate portion 49 A and the annular plate portion 49 B in opposite directions and resiliently press the fixed lip portion 49 A 1 and the sliding lip portion 49 B 1 against the seal mounting groove 47 A and the slidable contact ring 51 , respectively.

As shown in FIG. 4 , a space S is formed between the annular plate portion 49 B of the contact seal 48 and an inner peripheral wall surface of the seal mounting groove 47 A. Therefore, as indicated by arrows in FIG. 4 , a part of a gas sucked in into the suction chamber 12 flows into the inside of the spring member 50 of the contact seal 48 through a space between the end plate 43 A of the orbiting scroll member 42 and the slidable contact ring 51 , a space between the seal mounting member 47 and the slidable contact ring 51 and the space S between the contact seal 48 and the seal mounting groove 47 A. Due to the pressure of the gas flowing into the inside of the spring member 50 , the fixed lip portion 49 A 1 and the sliding lip portion 49 B 1 of the seal ring 49 , together with the spring member 50 , are pressed against the seal mounting groove 47 A and the slidable contact ring 51 , respectively.

Reference numeral 52 denotes an outer seal mounting member as a partition wall member fixedly provided between the large-diameter portion of the casing 1 and the fixed scroll member 41 . The seal mounting member 52 comprises an annular flange portion 52 A fixedly provided so as to abut against the large-diameter portion 1 A of the casing 1 and the ring-receiving portion 41 D of the fixed scroll member 41 , a cylindrical portion 52 B axially extending from an inner circumferential surface of the flange portion 52 A and an annular projecting portion 52 C projecting radially inward from the cylindrical portion 52 B.

The annular projecting portion 52 C of the seal mounting member 52 includes an annular seal mounting groove 52 D, which faces the slidable contact surface 47 B of the seal mounting member 47 and has a generally U-shaped cross-section. The seal mounting member 52 is provided outside the seal mounting member 47 in a manner such that the cylindrical portion 52 B and the annular projecting portion 52 C surround the seal mounting member 47 in a circumferential direction.

Reference numeral 53 denotes an intermediate chamber formed between the inner seal mounting member 47 and the outer seal mounting member 52 . The intermediate chamber 53 provides an annular space having a generally U-shaped cross-section between the seal mounting member 47 , and the cylindrical portion 52 B and the annular projecting portion 52 C of the seal mounting member 52 . When a gas from the compression chambers 8 and the suction chamber 12 has leaked through the contact seal 48 , it is temporarily accommodated in the intermediate chamber 53 .

Reference numeral 54 denotes an auxiliary seal mechanism as an auxiliary seal means provided in the seal mounting groove 52 D of the seal mounting member 52 . The auxiliary seal mechanism 54 comprises the face seal 55 and a backup ring 56 .

The face seal 55 comprises, for example, a seal ring made of an elastic resin material and having a rectangular cross-section. The face seal 55 is fitted into the seal mounting groove 52 D and disposed at the opening of the seal mounting groove 52 D. The backup-ring 56 is made of an elastic rubber material and disposed in contact with the bottom of the seal mounting groove 52 D (at a maximum depth of the groove 52 D). The backup ring 56 resiliently presses the face seal 55 toward the slidable contact surface 47 B of the seal mounting member 47 .

In the auxiliary seal mechanism 54 , the face seal 55 provides an gas-tight seal between the seal mounting members 47 and 52 by making slidable contact with the slidable contact surface 47 B under resilient force, to thereby enable the gas which has leaked into the intermediate chamber 53 to be sealably contained in the intermediate chamber 53 .

Reference numeral 57 denotes an escape pipe as an escape means which is open to the intermediate chamber 53 formed between the seal mounting members 47 and 52 . The escape pipe 57 is fixed at one end thereof to the ring-receiving portion 41 D of the fixed scroll member 41 , and extends through the suction chamber 12 and the flange 45 C of the supply pipe 45 to the outside (an outdoor space).

In the second embodiment, the fixed lip portion 49 A 1 and the sliding lip portion 49 B 1 of the contact seal 48 provided around the outer circumferential surface of the orbiting scroll member 42 are resiliently pressed against the seal mounting groove 47 A and the slidable contact ring 51 , respectively. Therefore, the space between the fixed scroll member 41 and the orbiting scroll member 42 can be reliably sealed, thus preventing leakage of a gas from the compression chambers 8 or the suction chamber 12 through the space between the fixed scroll member 41 and the orbiting scroll member 42 to the outside. Thus, in the second embodiment, substantially the same working effect as obtained in the first embodiment can be obtained.

Further, in the second embodiment, the seal mounting member 52 is provided so as to surround the seal mounting member 47 in a circumferential direction, and the intermediate chamber 53 is formed between the seal mounting members 47 and 52 . Therefore, if a gas leaks from the compression chambers 8 through the contact seal 48 , it can be temporarily accommodated in the intermediate chamber 53 . Further, the auxiliary seal mechanism 54 is provided in the seal mounting member 52 so as to provide a seal between the seal mounting members 47 and 52 , so that the gas can be sealably contained in the intermediate chamber 53 . Thus, the space between the fixed scroll member 41 and the orbiting scroll member 42 can be double-sealed by means of the contact seal 48 and the auxiliary seal mechanism 54 , thereby enhancing the sealing performance between the fixed scroll member 41 and the orbiting scroll member 42 .

Further, in the second embodiment, the space S is formed between the contact seal 48 and the seal mounting groove 47 A, and a gas is positively taken into the inside of the spring member 50 through the space S. Therefore, due to the effect of the spring resiliency of the spring member 50 and the pressure of the gas inside the spring member 50 , the fixed lip portion 49 A 1 and the sliding lip portion 49 B 1 of the seal ring 49 are pressed with a large force against the seal mounting groove 47 A and the slidable contact ring 51 , respectively. Thus, leakage of a gas to the outside can be reliably prevented. This action of the spring member 50 and the pressure of the gas inside the spring member 50 also serves to enhance the sealing performance of the auxiliary seal mechanism 54 .

In addition, since the escape pipe 57 open to the intermediate chamber 53 is provided, the gas in the intermediate chamber 53 is allowed to escape through the escape pipe 57 to the outside (an outdoor space) and diffuse into the atmosphere. Thus, there is no problem of the gas remaining in an indoor space in which the compressor is installed.

Further, the contact seal 48 and the auxiliary seal mechanism 54 are spaced in an axial direction (in a direction of thrust). Therefore, as compared to the auxiliary seal mechanism 54 being disposed on a radially outer side of the contact seal 48 , the compressor can be reduced in size with respect to a radial direction.

FIGS. 5 to 7 show a third embodiment of the present invention. The third embodiment is characterized in that in the seal ring providing the contact seal between the fixed scroll member and the orbiting scroll member, the fixed lip portion fitting against the seal mounting groove has a small contact area in contact with the seal mounting groove, while the sliding lip portion has a large contact area in slidable contact with the fixed scroll member.

In the third embodiment, the same portions or elements as used in the first embodiment are designated by the same reference numerals and characters, and an overlapping explanation is omitted.

Reference numeral 91 denotes a fixed scroll member according to this embodiment. The fixed scroll member 91 comprises an end plate 91 A, a wrap portion 91 B, an outer edge portion 91 C, a ring-receiving portion 91 D and radiating fins 91 E. The ring-receiving portion 91 D is cut so as to form a recess 91 D 1 .

Reference numeral 92 denotes an orbiting scroll member according to this embodiment. The orbiting scroll member 92 comprises an orbiting scroll main body 93 and a rear plate 94 . The orbiting scroll main body 93 comprises an end plate 93 A, a wrap portion 93 B and radiating fins 93 C. An annular stepped portion 93 D is formed in the end plate 93 A. A boss portion 94 A is formed in the rear plate 94 .

Reference numeral 95 denotes a seal mounting member used in this embodiment, which is provided on an outer circumferential surface of the orbiting scroll member 92 . The seal mounting member 95 is fittingly connected to the annular stepped portion 93 D of the orbiting scroll member 92 and includes a seal mounting groove 95 A formed therein.

Reference numeral 96 denotes a contact seal as a seal member used in this embodiment, which is provided in the seal mounting groove 95 A of the seal mounting member 95 . The contact seal 96 comprises a seal ring 97 and a spring member 98 which are described later.

The seal ring 97 , which provides a part of the contact seal 96 , comprises an elastic body made of a resin material. It has an opening on a radially inner side thereof and has a generally U-shaped cross-section. The seal ring 97 is provided in the seal mounting groove 95 A of the seal mounting member 95 .

The seal ring 97 comprises: a fixed-side annular plate portion 97 A provided at the bottom of the seal mounting groove 95 A and having a fixed lip portion 97 A 1 ; a sliding-side annular plate portion 97 B provided at the opening of the seal mounting groove 95 A and having a sliding lip portion 97 B 1 ; and a connecting cylindrical portion 97 C connecting the annular plate portions 97 A and 97 B.

In the seal ring 97 , the fixed lip portion 97 A 1 is fittingly contained in the seal mounting groove 95 A and the sliding lip portion 97 B 1 is adapted to be slidably moved relative to a slidable contact ring 99 (described later) provided in the ring-receiving portion 91 D of the fixed scroll member 91 . Thus, the space between the fixed scroll member 91 and the orbiting scroll member 92 is gastightly sealed.

It should be noted that the fixed lip portion 97 A 1 of the seal ring 97 projects from the annular plate portion 97 A so as to have a generally triangular or semi-circular cross-section. On the other hand, the sliding lip portion 97 B 1 of the seal ring 97 projects from the annular plate portion 97 B so as to have a generally rectangular cross-section. The sliding lip portion 97 B 1 has an entirely flat surface in contact with the slidable contact ring 99 .

Therefore, when T 1 represents a contact area of the fixed lip portion 97 A 1 in contact with the seal mounting groove 95 A and T 2 represents a contact area of the sliding lip portion 97 B 1 in contact with the slidable contact ring 99 , the relationship between T 1 and T 2 is expressed by the following equation (1).

T 1 <T 2   (1)

Consequently, when P 1 represents a surface pressure acting on the surface of the fixed lip portion 97 A 1 in contact with the seal mounting groove 95 A and P 2 represents a surface pressure acting on the surface of the sliding lip portion 97 B 1 in contact with the slidable contact ring 99 , the relationship between P 1 and P 2 is expressed by the following equation (2).

P 1 >P 2   (2)

Further, as shown in FIG. 6 , when L 1 represents a thickness of the fixed lip portion 97 A 1 of the seal ring 97 and L 2 represents a thickness of the sliding lip portion 97 B 1 , the relationship between L 1 and L 2 is expressed by the following equation (3).

 L 2 >L 1   (3)

The spring member 98 is fittingly connected to an inner circumferential surface of the seal ring 97 . The spring member 98 is made of a metallic material and has a U-shaped cross-section. It resiliently presses the fixed lip portion 97 A 1 and the sliding lip portion 97 B 1 of the seal ring 97 against the seal mounting groove 95 A of the seal mounting member 95 and the slidable contact ring 99 , respectively. The slidable contact ring 99 is fittingly connected to the ring-receiving portion 91 D of the fixed scroll member 91 .

Next, an operation of the scroll gas compressor in the third embodiment is described. Since the seal ring 97 is press fitted into the seal mounting groove 95 A of the seal mounting member 95 , when the contact seal 96 is brought into slidable contact with the slidable contact ring 99 during an orbital motion of the orbiting scroll member 92 , a large frictional force is generated between the contact seal 96 and the seal mounting groove 95 A. This frictional force provides a resistance to the sliding motion of the contact seal 96 , and the contact seal 96 is slowly rotated relative to the seal mounting groove 95 A or becomes substantially stationary relative to the seal mounting groove 95 A.

Consequently, in the contact seal 96 , the fixed lip portion 97 A 1 is subject to a rotary sliding motion at a low speed relative to the seal mounting groove 95 A, and the sliding lip portion 97 B 1 of the contact seal 96 , which is in contact with the slidable contact ring 99 of the fixed scroll member 91 , is subject to an orbital sliding motion at a high speed relative to the slidable contact ring 99 .

In the third embodiment, in the seal ring 97 of the contact seal 96 , the contact area T 1 of the fixed lip portion 97 A 1 in contact with the seal mounting groove 95 A and the contact area T 2 of the sliding lip portion 97 B 1 in contact with the slidable contact ring 99 are determined so as to have a relationship indicated by the equation (1).

Therefore, in the seal ring 97 , the surface pressure P 2 of the sliding lip portion 97 B 1 for a high-speed orbital sliding motion becomes lower than the surface pressure P 1 of the fixed lip portion 97 A 1 [see the equation (2)]. Consequently, the rate of wear of the sliding lip portion 97 B 1 can be maintained at a low level, thus increasing durability and a life of the sliding lip portion 97 B 1 .

After assembly of the scroll gas compressor, a slight gap may be partially formed between the fixed lip portion 97 A 1 of the contact seal 96 and the seal mounting groove 95 A or between the sliding lip portion 97 B 1 and the slidable contact ring 99 , due to poor machining accuracy or assembling errors of various parts of the compressor.

In this case, a running-in operation is required to be conducted. In the running-in operation, the contact seal 96 is positively worn by the seal mounting groove 95 A and the slidable contact ring 99 , to thereby reduce the above-mentioned gap and prevent leakage of a gas through the contact seal 96 .

In the third embodiment, the surface pressure P 1 of the fixed lip portion 97 A 1 for a low-speed rotary sliding motion is set to be high, as indicated by the equation (2). Therefore, the rate of wear of the fixed lip portion 97 A 1 is increased, and the time required for the running-in operation can be reduced.

Further, since the surface pressure P 1 of the fixed lip portion 97 A 1 is increased, the sealing performance of the fixed lip portion 97 A 1 can be increased. Further, since the fixed lip portion 97 A 1 is subject to a low-speed rotary sliding motion, the rate of wear of the fixed lip portion 97 A 1 does not become extremely high even when the surface pressure P 1 is set to be high, thus ensuring durability of the fixed lip portion 97 A 1 .

Further, since the surface pressure P 1 of the fixed lip portion 97 A 1 of the contact seal 96 can be set to be high by reducing the thickness L 1 of the fixed lip portion 97 A 1 , the fixed lip portion 97 A 1 readily fits against the bottom of the seal mounting groove 95 A, and the sealing performance of the fixed lip portion 97 A 1 can be increased, thus preventing leakage of a gas.

Further, with respect to the sliding lip portion 97 B 1 of the contact seal 96 , the thickness L 2 is set to be large and the surface pressure P 2 is set to be low. Therefore, the rate of wear of the sliding lip portion 97 B 1 can be decelerated.

In the above-mentioned embodiments, the contact seal is attached to the end plate of the orbiting scroll member. This does not limit the present invention. The contact seal may be attached to the ring-receiving portion of the fixed scroll member.

In the first to third embodiments of the present invention, a seal member comprising an elastic member having an opening on a radially inner side thereof and having a U-shaped cross-section is provided around an outer circumferential surface of the orbiting scroll member, so as to seal the compression chambers relative to outside air between the orbiting scroll member and the fixed-side member. Therefore, the seal member resiliently abuts against the orbiting scroll member and the fixed-side member, thus sealing the space between the two scroll members and preventing leakage of a gas supplied to the suction openings or a gas compressed in the compression chambers to the outside through the space between the orbiting scroll member and the fixed-side member.

In the first to third embodiments of the present invention, the fixed lip portion of the seal member fits against the seal mounting groove and the sliding lip portion is slidably moved relative to the fixed scroll member. This provides an gas-tight seal between the seal mounting groove and the fixed scroll member and the sealing performance of the seal member can be increased.

In the third embodiment, an annular seal mounting groove for mounting of the seal member is provided on the outer circumferential surface of the orbiting scroll member, and the seal member is arranged, such that the fixed lip portion has a small contact area in contact with the seal mounting groove and the sliding lip portion has a large contact area in contact with the fixed scroll member. Therefore, the fixed lip portion of the seal member can be brought into resilient contact with the seal mounting groove under high surface pressure, thus increasing the sealing performance of the fixed lip portion of the seal member relative to the seal mounting groove. Further, the fixed lip portion is subject to a rotary sliding motion at a low speed relative to the seal mounting groove. Therefore, even when the surface pressure of the fixed lip portion is set to be high, the rate of wear of the fixed lip portion does not become extremely high, thus ensuring durability of the fixed lip portion.

Further, the sliding lip portion of the seal member can be brought into contact with the fixed scroll member under low surface pressure. Thus, the rate of wear of the sliding lip portion can be maintained at a low level and durability of the sliding lip portion can be increased.

In the second embodiment, a partition wall member is provided in the fixed-side member so as to form an intermediate chamber between the fixed-side member and the orbiting scroll member. Further, an auxiliary seal means is provided between the partition wall member and the orbiting scroll member so as to enable a gas which has leaked into the intermediate chamber to be sealably contained in the intermediate chamber. Therefore, if a gas from the compression chambers leaks through the seal member, it is accommodated in the intermediate chamber, and prevented from leaking from the intermediate chamber to the outside by the auxiliary seal means.

Further, the gas in the intermediate chamber is allowed to escape to the outside through an escape means. Therefore, the gas in the intermediate chamber can be discharged through the escape means to an outdoor space and diffused into the atmosphere. Thus, the gas in the intermediate chamber is prevented from leaking to an indoor space in which the compressor is installed.

Further, in the first to third embodiments, a part of the gas prevented from leaking to the outside by the sliding lip portion is taken into the inside of the spring member, thus increasing the pressure of the gas inside the spring member. Consequently, due to the effect of spring resiliency of the spring member and the pressure of the gas inside the spring member, the fixed lip portion of the seal ring is pressed with a large force against the bottom of the seal mounting groove, while the sliding lip portion is pressed with a large force against the fixed scroll member. Therefore, leakage of a gas to the outside can be reliably prevented.

The entire disclosure of Japanese Patent Applications Nos. 2000-207138 filed on Jul. 7, 2000 and 2001-024354 filed on Jan. 31, 2001 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.

Claims

1. A scroll compressor comprising:a fixed-side member comprising a casing and a fixed scroll member provided in the casing, said fixed scroll member including an end plate and a spiral wrap portion standing on the end plate; a driving shaft rotatably provided in the casing; an orbiting scroll member orbitably provided at a distal end of the driving shaft, said orbiting scroll member including an end plate and a spiral wrap portion standing on the end plate, said wrap portion of the orbiting scroll member being adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers; a suction opening provided in the fixed-side member so as to communicate with the outermost compression chamber of said plurality of compression chambers; a discharge opening provided in the fixed-side member so as to discharge a compressed gas from an inner compression chamber of said plurality of compression chambers to the outside; and a seal member comprising an elastic member provided around an outer circumferential surface of the orbiting scroll member, so as to seal the plurality of compression chambers relative to outside air between the orbiting scroll member and the fixed-side member, said seal member having an opening on a radially inner side thereof and having a generally U-shaped cross-section.

2. The scroll compressor according to claim 1, further comprising an annular seal mounting groove provided on the outer circumferential surface of the orbiting scroll member and having an opening facing the fixed scroll member,said seal member including a fixed lip portion adapted to fit against the seal mounting groove and a sliding lip portion slidable relative to the fixed scroll member.

3. The scroll compressor according to claim 2, wherein a contact area of the fixed lip portion in contact with the seal mounting groove is smaller than a contact area of the sliding lip portion in contact with the fixed scroll member.

4. The scroll compressor according to claim 2, wherein the sliding lip portion has a greater thickness than the fixed lip portion.

5. The scroll compressor according to claim 1, further comprising:a partition wall member provided in the fixed-side member so as to surround the orbiting scroll member in a circumferential direction and form an intermediate chamber between the wall member and the orbiting scroll member, the intermediate chamber being adapted to accommodate the gas which has leaked from the compression chambers through the seal member; and an auxiliary seal means provided between the partition wall member and the orbiting scroll member, the auxiliary seal means being adapted to enable the gas which has leaked into the intermediate chamber to be sealably contained in the intermediate chamber.

6. The scroll compressor according to claim 5, further comprising an escape means adapted to allow an escape of the gas accommodated in the intermediate chamber to the outside.

7. The scroll compressor according to claim 1, wherein the seal member has a passage for allowing a part of the gas to flow into the inside of the seal member so as to increase sealing performance of the seal member.

8. A scroll compressor comprising:a casing; a fixed scroll member provided in the casing, said fixed scroll member including an end plate and a spiral wrap portion standing on the end plate; a driving shaft rotatably provided in the casing; an orbiting scroll member orbitably provided at a distal end of the driving shaft, said orbiting scroll member including an end plate and a spiral wrap portion standing on the end plate, said wrap portion of the orbiting scroll member being adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers; a suction opening communicated with the outermost compression chamber of said plurality of compression chambers; a discharge opening adapted to discharge a compressed gas from an inner compression chamber of said plurality of compression chambers to the outside; and a seal apparatus provided on an outer circumferential surface of the orbiting scroll member, so as to seal the plurality of compression chambers relative to outside air between the orbiting scroll member and the fixed scroll member, said seal apparatus comprising: a grooved, annular seal mounting member having an opening, said annular seal mounting member being attached to the outer circumferential surface of the orbiting scroll member so that the opening of the groove faces the fixed scroll member; and a ring-shaped seal member for providing an gas-tight seal between the fixed scroll member and the orbiting scroll member, said seal member being attached to the groove of the annular seal mounting member so as to allow a part of the gas to flow into the inside of the seal member and increase sealing performance of the seal member.

9. The scroll compressor according to claim 8, wherein the seal member comprises an elastic seal ring having an opening on a radially inner side thereof and having a generally U-shaped cross-section and a spring member provided on an inner circumferential surface of the seal ring.

10. The scroll compressor according to claim 9, wherein the seal ring comprises a fixed-side annular plate portion provided at the bottom of the groove of the seal mounting member, a sliding-side annular plate portion provided at the opening of the groove and a connecting cylindrical portion connecting a radially outer end of the fixed-side annular plate portion and a radially outer end of the sliding-side annular plate portion.

11. The scroll compressor according to claim 10, wherein the fixed-side annular plate portion has a fixed lip portion formed at a radially inner end thereof, said fixed lip portion being in contact with the bottom of the groove, and the sliding-side annular plate portion has a sliding lip portion formed at a radially inner end thereof, said sliding lip portion projecting from the groove and being slidable relative to a slidable contact ring provided in the fixed scroll member.

12. The scroll compressor according to claim 11, wherein the spring member is made of an elastic material and has a generally U-shaped cross-section, the spring member being fittingly connected between the fixed-side and sliding-side annular plate portions, to thereby press the fixed-side annular plate portion and the sliding-side annular plate portion in opposite directions and resiliently press the fixed lip portion and the sliding lip portion against the groove and the slidable contact ring, respectively.

13. The scroll compressor according to claim 12, wherein a passage is formed between the sliding-side annular plate portion and an inner peripheral wall surface of the annular seal mounting member which defines a part of the groove, so as to allow a part of the gas to flow into the inside of the spring member.

14. The scroll compressor according to claim 13, wherein the passage is further formed between the spring member and the inner peripheral wall surface of the annular seal mounting member.

15. The scroll compressor according to claim 11, wherein a contact area of the fixed lip portion in contact with the bottom of the groove is smaller than a contact area of the sliding lip portion in contact with the slidable contact ring of the fixed scroll member.

16. The scroll compressor according to claim 11, wherein the sliding lip portion has a greater thickness than the fixed lip portion.