Rotary expansible chamber devices – With plural working fluid inlet or outlet passages
Reexamination Certificate
2001-11-30
2003-04-08
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
With plural working fluid inlet or outlet passages
C418S055100, C418S055400, C524S495000, C524S496000
Reexamination Certificate
active
06544014
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to scroll-type compressors.
2. Description of Related Art
A known scroll-type compressor includes a fixed scroll member and an orbiting scroll member within a housing. The fixed scroll member has a first end plate and a first spiral element that extends axially from the first end plate. The orbiting scroll member has a second end plate and a second spiral element that extends axially from the second end plate. The first spiral element and the second spiral element interfit at an angular and radial offset to form a plurality of line contacts that define at least one pair of sealed-off fluid pockets. The orbiting scroll member rotates in an orbital motion with respect to the fixed scroll member. The sealed-off fluid pockets move radially inward due to the orbital motion of the orbiting scroll member. The pockets also decrease in volume, thereby compressing refrigerant gas. A plurality of bypass apertures for discharging oil included in the refrigerant gas are formed through the first end plate of the fixed scroll member. A tip seal is embedded in a front end portion of the second spiral element of the orbiting scroll member. Various measures have been undertaken to reduce interference between the tip seal and the bypass apertures. These measures include modifications to those portions of the tip seal facing the bypass apertures. Examples of such known scroll-type compressors are disclosed in Japanese Unexamined Patent Application Publication No. H11-148472 and Japanese Utility Model Application Publication Nos. S61-17490 and S61-41882.
In the scroll-type compressor disclosed in Japanese Unexamined Patent Application Publication No. H11-148472, interference between a tip seal
100
and a plurality of bypass apertures is avoided by separating tip seal
100
into a plurality of segments, as shown in FIG.
1
. Moreover, in the scroll-type compressor disclosed in Japanese Utility Model Application Publication No. S61-17490, an interference between a tip seal
100
′ and a plurality of bypass apertures is avoided by the provision of a plurality of concave portions
100
′
a
formed on a front end of tip seal
100
′, as shown in
FIGS. 2
a
and
2
b
, Moreover, in the scroll-type compressor disclosed in Japanese Utility Model Application Publication No. S61-41882, interference between tip seal
100
″ and a plurality of bypass apertures is avoided by the use of a plurality of notched portions
100
″
b
formed on side walls of tip seal
100
″, as shown in
FIGS. 3
a
and
3
b
. Thus, by avoiding interference between tip seal
100
(
100
′ or
100
″) and the bypass apertures, wear of tip seal
100
(
100
′ or
100
″) due to contact between tip seal
100
(
100
′ or
100
″) and the bypass apertures may be reduced or eliminated. Accordingly, tip seal
100
(
100
′ or
100
″) may be made of a polytetrafluoroethylene (PTFE) material, for example.
Nevertheless, in the scroll-type compressor of Japanese Unexamined Patent Application Publication No. H11-148472, in which the tip seal
100
at the front end portion of the second spiral element of the orbiting scroll member is separated into a plurality of segments, the manufacturing time required to form a groove that receives the segmented tip seal may increase. Moreover, additional manufacturing time may be required to embed segmented tip seal
100
in the front end portion of the second spiral element. Moreover, additional time may be required for inventory management of segmented tip seal
100
due to an increase in the number of parts of segmented tip seal
100
. Further, tip seal
100
may be attached improperly. Additionally, performance of this scroll-type compressor may decrease due to refrigerant gas leaking through defective portions of tip seal
100
, which portions may be caused by errors in the manufacture of tip seal
100
. Similarly, in the scroll-type compressors of Japanese Utility Model Application Publication No. S61-17490 and Japanese Utility Model Application Publication No. S61-41882, the performance of these scroll-type compressors may decrease due to refrigerant gas leaking between fluid pockets via concave portions
100
′
a
of tip seal
100
′ or notched portions
100
″
b
of tip seal
100
″.
SUMMARY OF THE INVENTION
A need has arisen to simplify the manufacture of tip seals and reduce leakage in known scroll-type compressors with an end plate of a fixed scroll member having bypass apertures and a front end portion of a spiral element of an orbiting scroll having a tip seal.
In an embodiment of this invention, a scroll-type compressor comprises a housing, a fixed scroll member, an orbiting scroll member, a drive mechanism, and a rotation prevention mechanism. The housing has an outlet port and an inlet port. The fixed scroll member comprises a first end plate and a spiral element formed thereon. The spiral element extends from a first side of the first end plate. The fixed scroll member is attached to the housing. The orbiting scroll member comprises a second end plate and a spiral element formed thereon. The spiral element extends from the first side of the second end plate. The spiral elements interfit at an angular and a radial offset to form a plurality of line contacts that define at least one pair of sealed-off fluid pockets. The drive mechanism comprises a drive shaft that is rotatably supported by the housing. Rotation of the drive shaft effects an orbital motion of the orbiting scroll member to thereby change a volume of the fluid pockets. A rotation prevention mechanism prevents the orbiting scroll member from rotating. A plurality of bypass apertures are formed through the first end plate of the fixed scroll member. A tip seal made of Polyphenylene-sulfide or Polyetheretherketone is embedded in a front end portion of the spiral element of the orbiting scroll member.
Other objects, features, and advantages of embodiments of this invention will be apparent to, and understood by, persons of ordinary skill in the art from the following description of preferred embodiments with reference to the accompanying drawings.
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patent: 4437820 (1984-03-01), Terauchi et al.
patent: 4453899 (1984-06-01), Hiraga et al.
patent: 4627799 (1986-12-01), Terauchi
patent: 4701115 (1987-10-01), Shimizu et al.
patent: 4722676 (1988-02-01), Sugimoto
patent: 4753583 (1988-06-01), Hiraga et al.
patent: 5124397 (1992-06-01), Kanazawa et al.
patent: 5575634 (1996-11-01), Tanaka et al.
patent: 5636976 (1997-06-01), Niwa et al.
patent: 5674058 (1997-10-01), Matsuda et al.
patent: 6126422 (2000-10-01), Crum et al.
patent: 62070681 (1987-04-01), None
patent: 62197684 (1987-09-01), None
patent: 08105391 (1996-04-01), None
Baker & Botts L.L.P.
Denion Thomas
Sanden Corporation
Trieu Theresa
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