AU4238799A - Rotation preventing device for orbiting member of fluid displacement apparatus - Google Patents

Description

S F Ref: 473706

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Sanden Corporation Kotobuki-cho Isesaki-shi Gunma 372-8502

JAPAN

Keiichi Tomaru Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Rotation Preventing Device for Orbiting Member of Fluid Displacement Apparatus *o *o o The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845 1 9 9 7-2 7; 0 26 A) W MgB

SPRUSON

;0270245335 1/ 0270245335 ROTATION PREVENTING DEVICE FOR ORBITING MEMBER OF FLUID DISPLACEMENT APPARATUS SBACKGROUND OF THE INVENTION Field of Invention The present invention relates to a fluid displacement apparatus, and more particularly, to a rotation preventing and thrust bearing device for an orbiting member of a fluid displacement apparatus.

Description of the Related Art Scroll-type fluid displacement apparatuses are known in the art. U.S. Patent No. 4,892,469, which is incorporated herein by reference, describes an apparatus including two scroll members each having an end plate and a spiral element The scroll members maintain an angular and a radial offset, so that both spiral elements interfit to create a plurality of line contacts between the spiral curved surfaces which define the volume in the fluid pockets. The 15. volume of the fluid pockets increases or decreases depending on the direction of orbital motion.

Thus, a scroll-type fluid displacement apparatus may compress, expand, or pump fluid.

In a scroll-type fluid displacement apparatus, a first scroll is fixed to a housing, and a second scroll, or the orbiting scroll, is supported eccentrically on a crank pin of a rotation shaft to cause orbital motion. The scroll-type fluid displacement apparatus also includes a 20 rotation preventing device that prevents rotation of the orbiting scroll to maintain the scrolls in a predetermined angular relationship during operation of the apparatus.

Because the orbiting scroll in the scroll-type fluid displacement apparatus is supported on a crank pin in a cantilever manner, an axial shift of the orbiting scroll occurs during operation of the apparatus. An axial slant also occurs because the movement of the orbiting DCOI 226409.1 1 33- 7-27; 0:26 ;ty- SPRUSON ;0270245335 2/ 0270245335 4 scroll is not a rotary motion around the center of the orbiting scroll. Instead, the movement is an orbiting motion caused by the eccentric movement of a crank pin driven by the rotation of the drive shaft. Several problems may result from this axial slant including improper sealing of the line contacts, vibration of the apparatus during operation, and noise caused by the spiral elements striking each other.

A proposed solution to the problems is the use of a thrust bearing device for carrying the axial loads. Thus, a scroll-type fluid displacement apparatus may be provided with a rotation preventing device which also performs a thrust bearing function, within the housing.

Such a rotation preventing and thrust bearing device includes an orbital portion, a fixed portion, and a plurality of bearings, such as balls or spheres. The orbital portion includes a first annular washer and separator. The fixed portion includes a second annular washer and separator. The second washer is placed within an annular groove formed on an axial end surface of the housing, and the second ring covers the axial end surface of the second race, A clearance or space is S maintained between the first ring of the orbital portion and the second ring of the fixed portion.

i'-Tr The orbital and fixed rings each have a plurality of holes arranged axially. An S equal number of holes are formed within the rings. Each bearing rolls with respect to the orbital race and also rolls with respect to the fixed race. The pairs of holes from pockets. The bearings roll and slide along the edges of the pockets.

As a result, the rotation of the orbiting member is prevented by the bearings, and the thrust load from the orbiting member is supported at the fixed race through the bearings.

However, the bearings in the pockets of the rings interact with the edges to prevent rotation of the orbiting scroll. The edge of the pockets are in contact with the bearings and increases the abrasion of the bearings due to use.

DC 01226409.1 39- 7-27 0 :26 0)%g SPRUSON ;0270245335 3/ 0270245335 A known scroll-type fluid displacement apparatus is described in Japanese Patent Publication No. H5-33811. A rotation preventing and thrust bearing device is located between Sthe inner end surface of a front end plate and the axial end surface of an end orbiting scroll.

Such rotation preventing and thrust bearing devices include fixed indentations formed on the inner end surface of the orbiting scroll and a plurality of bearing elements, such as balls or spheres. Each bearing element is placed in aligned indentations. Rotation of the orbiting scroll is prevented by the interaction of the bearings and the indentations. In addition, the axial thrust load from the orbiting scroll is supported by the front end plate. Fixed and orbiting cover plates are made from discrete parts of the front end plate and of the orbiting scroll. The plates are formed by a working press, and are disposed on the inner end surface of the front end plate and the end surface of the orbiting scroll to prevent wear of the indentations.

Further, fixed and orbiting cover plates include a pair of grooved portions. Each grooved portion has a bottom formed as a circular track and an arc-shaped wall with a diameter greater than that of the bearing. The circular track has a diameter substantially equal to the orbiting radius of the orbiting scroll. Thus, the bearing travels in a known manner along the circular track within the groove.

Referring to Figs. 11, 12, 13, 14 and 15, a orbiting race 51 includes a ring member and a plurality of circular pockets 51a that have projections 51d that extend from the a center and are formed on a first axial surface. Circular pockets Sla are prepared in accordance with an embossing process. Orbiting race 51 includes convex portions 51b on a second axial surface that connect to projections 51d. Further, orbiting race 51 includes a plurality of holes S51c formed radially within orbiting race 51 for securing to orbiting scroll member 106.

DC01:226409.1 4 9 9 7 2 7 0 2 6 Witff SPRUSON 0 2 7 0 2 4 5 3 3 5 4 3 0270245335 Referring to Fig. 12, 15 and 16, a fixed race 52 includes a ring member and a plurality of circular pockets 52a- Circular pockets 52a have projections 52d that extend from the center, and are formed on the first axial surface. Circular pockets 52a are prepared in accordance with an embossing process. Fixed race 52 includes convex portions 52b on the second axial surface that connect to projections 52d, Further, fixed race 52 includes a plurality of holes 52c formed radially within fixed race 52 for securing to the inner wall of front housing 102.

Referring to Figs. 17 and 18, a scroll compressor includes a rotation preventing and thrust bearing device 60. Rotation preventing and thrust bearing device 60 includes a fixed race 61, a fixed ring 62, an orbiting race 65 and an orbiting ring 64. Fixed race 61 contacts fixed ring 62 at a facing surface and secures to the axial end of orbiting scroll member 106 by pin members.

A contacting surface 61a of fixed race 61 and holes 66 of fixed ring 62 form a space that accommodates the balls. Further, contacting surface 65a of orbiting race 65 and holes 67 of orbiting ring 64 forms a space that also accommodates the balls, Thus, rotation preventing i device 60 accommodates the balls between the races and rings. Therefore, fixed ring 62 and orbiting ring 64 are assembled, such that the surfaces of fixed ring 62 and orbiting ring 64 have a clearance, or space, to accommodate the balls.

Referring again to Fig. 12, a rotation preventing and thrust bearing device 50 has *orbiting race 5 1 and fixed race 52. Orbiting race 5 1 and fixed race 52 include an axial clearance, or space, such that orbiting race 51 is not in contact with fixed race 52.

Referring again to Figs. 17 and 18, rotation preventing and thrust bearing device has an orbiting race 61 and a fixed race 62. Orbiting race 61 and fixed race 62 include an axial clearance, such that orbiting race 61 is not in contact with fixed race 62.

DCOi .2264og.i 99- 7-27; 0:26 SPRUSON ;0270245335 5/ 0270245335 orbiting race 51 and fixed race 52 of Fig. 12 are subjected to a rotation preventing force, or moment, and an axial load that is caused by a reaction force of compressed gas in the orbiting scroll member, with interacting balls 53 having a slight surface contact Therefore, the contacting surface pressure -formed between bails 53 and races 5 1 and 52 increases during compressor operations.

Further, contacting surface pressure increases rapidly as bails 53 move on the center projection as orbiting race 51 diverges froma a predeteriined alignmnent with fixed race 52.

The pressure increase may occur despite orbiting race 51 and fixed race 52 having a center projection in the plurality of pockets that provides increased contact surface with balls 53.

In this arrangement, orbiting race 51, fixed race 52 and balls 53 are made of metal to accommodate the contacting surface pressure. Thus, noise and vibration occur as balls 53 roll between orbiting race 5 1 and fixed race 52. Therefore, the weight of the moving parts of the fluid displacement apparatus, particularly weight of the counter-balance weight is difficult to decrease. Further, the diameter of the body of the fluid displacement apparatus is difficult to decrease.

DCOI 1226409.1 33- 7-27; 0:26 I 5 Witff SPRUSON ;0270245335 44 ff 6 0270245J335 -SUMMlARY OP THE INVE-NTON Accordingly, it is an object of the present invention to provide a rotation preventing and thrust bearing device for an orbiting member of a fluid displacement apparatus that has increased operation~al durability.

It is another object of the present invention to provide a rotation preventing and thrut bearing device for an orbiting member of fluid displacement apparatus that had decreased manufacturing costs.

It is still another object of the present invention to provide a f luid displacement apparatus that reduces noise, vibration in operation, and size.

According to the present invention, a rotation preventing mechanism prevents rotation of an orbiting scroll member of a fluid displacement apparatus. The orbiting scroll member has a predeterm-ined orbit radius and a predeterm~ined angular relationship with a fixed n....scroll member during orbital motion. The rotation preventing mechanism includes a pair of :i 5 annular members that arc connected to the orbiting scroll member and has a plurality of bearing aa.. elements. Each bearing element is disposed between a pair of annular members. The pair of annular members substantially contact each other at facing suzfa=c thereof.

a.

Further objects, features, and advantages of this invention mtay be understood from the following detailed description of preferred embodiments, read in conjunction with the 020 attached drawings.

OC01:264O9. I 99- 7-27; 0:26 1 SPRUSON ;0270245335 7/ 3 0270245335 3IF DESCRfITION OF TEE DILAWMhJQ For a more complete understanding of the present invention and its advantages, referonce is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represenit like parts.

Fig. 1 is a cross-sectional view of a fluid displacement apparatus in accordance with a first embodiment of the present invention.

Fig, 2 is a cross-sectional view of a rotation preventing device depicted in Fig, 1 in accordance 'with a first embodiment of the present invention.

Fig. 3 is an enlarged, partial cross-sectional view of an orbiting race in accordance with a first embodiment of the present invention.

Fig. 4 is an enlarged, partial cross-sectional view of the fixed race depicted in Fig, 2 in accordance with a first embodiment of the present invention.

*409 Fig. 5 is a cross-sectional view of a fluid displacement apparatus in accordance with a second embodiment of the present invention.

V* Fig. 6 is a cross-sectional view of the rotation preventing device depicted in Fiig. in accordance with a second embodiment of the present invention Fig,. 7 is an enLarged, partial cross-sectional view of an orbiting race i accordance with a second embodiment of the present invention.

020 Fig. 8 is an enlarged, partial cross-sectional view of the fixed race depicted in Fig. 7 in accordance with a second embodiment of the present invention.

Fig. 9 is a cross-sectional view of a fluid displacement apparatus in accordance with a third embodiment of the present invention.

DCOI;.226409.1 339- 7-27; 0:26 4 W9 S PRUSO N 0470'245335 S/ 0270245335 Fig. 10 is a cross-sectional view of a rotation preventing device depicted in Fig. 9 in accordance with a third embodiment of the present invention.

Fig. 11 is a cross-sectional view of a known fluid displacement apparatus mechanism.

S Fig. 12 is a cross-sectional view of a known rotation preventing device depicted inFig. 11.

Fig. 13 is a front view of an orbiting race depicted in Fig. 12.

Fig. 14 is a partial, cross-sectional view of the orbiting race depicted in Fig. 13 Fig. 15 is a front view of a fixed race depicted in Fig. 12.

Fig. 16 is a partial, cross-sectional view of the fixed race depicted in Fig. 16.

Fig. 17 is a cross-sectional view of a known fluid displacement apparatus.

Fig. 18 is a cross-sectional view of a rotation preventing device depicted in Fig. 17.

*Got DCOI :226409.1 9 9- 7-2 7 0 2 6 Wjtgg SPRUSON ;0270245335 9/ 7-74:6 PUSN07253 /3 0270241335 DETAILD DESCRIPTION-0OF PRFERRED EMBODIhMNTS Embodiments of the present invention are illustrated in Figs. 1 18, wherein like numerals are used to denote elements that corresponds to like elements depicted in Figs, 1 18.

Referring to Fig. 1, a fluid displacement apparatus in accordance with the present invention is depicted as scroll-type refrigerant compressor unit 35. Compressor unit 35 includes a casing 101 having a front end opening. A front housing 102 is attached to the front end opening surface of the casing 101. A crank shaft 103 is enclosed by front housing projection 102~a. In a crank chamber 104 enclosed by casing 101 and front housing 102, a fixed scroll member 105 is fixed to casing 101. An orbiting scroll member 106 is positioned opposite of fixed scroll member 105, and is aligned, with and gyrates relative to, fixed scroll member 105's center axis, Orbiting scroll member 106 includes a side wall 107, a scroll 108 attached to a first side of side wall 107, and a boss 109 projecting from a second side of side wall 107. Boss 109 :00 includes a bushing 112. An eccentric hole 113 is formed in bushing 112 at a position radially 00 15 offset from the center of bushing 112. Bushing 112 is supported by abearing 114. Crank shaft 00 00::0* 103 at a first end of crank chamber 104 forms disk I110. Disk 110 is opposite crank shaft 103.

Crank pin IlIl fits through eccentric hole 113. Crank shaft 103 is supported by a bearing 115 :0 and forms a seal 116. Disk 1 10 of crank shaft 103 is supported by front housing 102 via bearing 117.

0 .0 -20 A balance weight 119 operates to balance orbiting scroll member 106 and crank shaft 103. A magnetic clutch 120 surrounds projection 102a of front hous~ing 102. Magnetic clutch 120 includes a rotor 121 that is hollow and round. Magnetic clutch 120 is supported via bearing I IS around projection 102a. Rotor 121 includes a magnet member 122 and a clutch 001-.226409.1 99- 7-27; 0:26 SPRUSON ;0270245335 10G/ 3 02 7024533 plate 123 on rotor 121's external end. Clutch plate 123 is fixed to crank shaft 103 by a fixed member- In crank chamber 104, boss 109 of side wall 107 in conjunction with an inner wall of -front housing 102 forms a rotation preventing device Referring to Figs. 2-4, rotation preventing device 10 of an embodiment of the present invention includes an orbiting race I formed at orbiting scroll member 106, a fixed race 2 fixed to an inner wall of front housing 102, and a plurality of balls 3 disposed between orbitng race 1 and fixed race 2. Balls 3, orbiting race 1, and fixed race 2 may be comprised of iron.

Alteratively, balls 3, orbiting race 1, and fixed 2 miay be comprised of a material that has a lower specific gravity than iron, such as aluminum, magnesium, titaniumn, or ceramic, or the like.

Referring to Figs. 2 and 3, orbiting race 1 includes a plate member formed ini an annular shape. The plate member has a plurality of circular pockets 5 within which balls 3 roll.

Circular pockets 5 are prepared by an embossing process such that their circumference forms a circular shape and their bottom portion forms a flat surface.' Further, orbiting race I includes a plurality of projections 6 corresponding to circular pockets 5 that are fonned by an embossing Referring to Figs. 2 and 4, fixed race 2 includes a plate member formed as a annular shape. The plate member has a plurality of circular pockets 8 within which balls 3 roll.

Circular pockets 8 are prepared by an embossing process such that their circumference forms a circular shape and their bottom portion forms a flat surface. Further, fixed race 2 includes a .20 plurality of projections 9 corresponding to circular pockets 8 tbat are formed by an embossing process.

Referring to Fig, 2, orbiting race I contacts fixed race 2 at side surfaces 4a and 7a of plate members, such that rotation preventing device 10 does not have spaces except for DCD 1226409. 1 99- 7-27; 0:26 SPRUSON ;0270245335 11/ 0270245335 circular pockets 5 and 8 that accommodate balls 3 in an axial direction. The depth of circular pockets 5 and 8 are RI and R2, respectively. The sum of RI and R2 is about equal to, or slightly greater, than, the diameter of balls 3.

The operation of compressor 35 is described briefly below. The line contact between the spiral elements of the scroll members moves toward the center of the spiral elements along the surface of the spiral elements. The fluid pockets, defined by the spiral elements, also move toward the center with a reduction in volume that compresses the fluid or gas in the fluid pockets- The fluid or gas is introduced into the suction chamber from an external fluid circuit through the inlet port, and is drawn into the fluid pockets formed at an outer end of the spiral element. Orbiting scroll member 106 orbits, and the fluid or gas in the fluid pockets compresses.

The compressed fluid, or gas, discharges into the discharge chamber through a hole from the central fluid pockets of the spiral element. Then, the fluid discharges to the external fluid circuit through an outlet port. As the rotation of drive shaft 103 drives orbiting scroll member 106, the center of orbiting race 1 orbits about a circle having a radius RO.

S' tS5 However, a rotation force, or moment, is created by the offset of the direction of the reaction force of compression. The direction of the drive force acts on orbiting scroll member 106. The reaction force tends to rotate orbiting scroll member 106 about the center. of orbiting race 1. The locus. of the contact points in each of balls 3 within pockets 5 and 8 is a circle having radius RO, Thus, the traveling radius of each ball 3 with respect to the axial end surface of fixed race 2 and orbiting race 1 is defined by RO. The rotation of orbiting scroll member 106 is inhibited by balls 3. Balls 3 contact with the walls of pockets 5 and 8 during operation, while the angular relationship between fixed scroll 105 and orbiting scroll member 106 is maintained.

DC 1226409.1 1 9 3 7 2 7 0 2 6 WI 95 SPRUSON ;0270245335 12/ 0270245335 Therefore, the inside wall of circular pocket 5 in orbiting race 1 and circular pocket 8 in fixed race 2 is subjected a rotation preventing force, or moment, with balls 3.

Further, surface portion 4a of circular pocket 5 and surface portion 7a of circular pocket 8 is subjected to an axial load. The reaction force of the compressed gas via orbiting scroll member 106 through balls 3 creates the axial load.

This embodiment my reduce the contacting surface pressure that is caused between balls 3, and races I and 2. Orbiting race I and fixed race 2 do not have the center projection in order to gain broader contact surface with ball 3. Thus, the contacting surface pressure does not increase at as rapid a rate, as the position of orbiting race 1, related to fixed race 2, diverges from predetermined alignment. Further, noise and vibration, which may be caused as balls 3 are rollingly coupled to orbiting race I and fixcd race 2, may be reduced as the contacting surface pressure decreases, Thus, in an embodiment of present invention, rotation preventing device facilitates dispersion of a rotation preventing force, or moment, and the axial load caused by the reaction force of the compressed gas. Accordingly, the arrangement may reduce the number of bals 3 within rotation preventing deie1.0. Tearnmntayedcthwigtof moving parts of the fluid displacement apparatus. Particularly, the weight of the counter-balance weight and the diameter of an apparatus body may be decreased. This reduction may decrease costs associated with the fluid displacement apparatus.

Further, as above mentioned, balls 3, orbiting race I and fixed 2 may be made of material having a specific gravity less than iron.

DCOI !226409. I -99- 7-27 0 26 ff (0E) TV95~b SPRUSON ;0270245335 13/ 0270245335 In accordance with the present invention, the contacting surface pressure does not increase at a rapid rate if the position of orbiting race 1, relative to fixed race 2, diverges from a predetermined alignment because orbiting race 1 and fixed race 2 have no center projections.

Figs. 5, 6, and 7 depict another embodiment of a rotation preventing device 20 in accordance with the present invention. Referring to Fig. 5, fluid displacement apparatus 40 is similar to fluid displacement apparatus 10 except for having a rotation preventing device Referring to Figs. 6-8, rotation preventing device 20 includes an orbiting race 11 that is secured to orbiting scroll member 106. Rotation preventing device 20 also includes fixed race 12 that is fixed to front housing 102 and a plurality of balls 3 that are disposed between orbiting race 11 and fixed race 12. Orbiting race 11 and fixed race 12 may be comprised of resin, such as an engineering-plastic.

Orbiting race 11 and fixed race 12 differ from orbiting race 1 and fixed race 2 in configuration. The thickness of orbiting race 11 and fixed race 12 is designed to be thicker than that of orbiting race 1 and fixed race 2.

5 Referring to Figs. 6 and 7, orbiting race 11 includes an annular plate member 13 that has a plurality of circular pockets 14 at a first side surface and a flat plane at a second side surface. Circular pockets 14 include a plane portion and a rounded wall extending from the plane portion.

Referring to Figs. 6 and 8, fixed race 12 includes an annular plate member 16 having a plurality of circular pockets 17 at a first side surface. The number of circular pockets 14 in orbiting race 11 and circular pockets 17 in fixed race 12 are equal. Orbiting race 11 and fixed race 12 face each other at a predetermined axial clearance. Circular pockets 14 correspond in location to circular pockets 17, such that at least each circular pocket portion faces each other DCOI:226409.1 33- 7-27; 0:26 _SPRUSON 02 70 24 5 33 5 14/ 0270245335 and has the same pitch, Further, the radial distance of circular pockets 14 and 17 from the center of their respective races 11 and 12 is about equal.

Rotation preventing device 20 in Figs. 6 and 8 includes orbiting race I11 and fixed race 12 that substantially contact each other at side surfaces of plate 15 and 18 Orbiting race 11 S and fixed race 12 have negligible space in the axial direction except for circular pockets 14 and 17 that accommodate balls 3. Circular pockets 14 and 17 have a depth R1 and R2, respectively.

The sum of depth RI and R2 is about equal to, or slightly greater than, the diameter of balls 3.

Thus, the rounded wall of circular pockets 14 in orbiting race 11 and circular pockets 17 in fixed race 12 are subjected a rotation preventing force, or moment, with balls 3.

Further, the broad surface, or first side surfaces, of plates 15 and IS is subjected to the axial load that is created by the reaction force of the compressed gas via orbitig scroll member 106 through balls 3.

The present invention realizes the following improvements. Because orbiting ~.race I1I and fixed race 12 are comprised of resin, rotation preventing device 20 may reduce noise I and vibration created by contact between balls 3, orbiting race 11, and fixed race 12. The diameter of the body of a fluid displacement apparatus may be decreased because the balance weight may be reduced, or is lightweight. Further, orbiting race 11 or fixed race 12 may be made from resin and the opposite race may be made of metal, such as aluminum, magnesium, titanium,, or ceramic, or the lik~e. Balls 3 also may be made of resin, Figs. 9 and 10 depict another embodiment of a rotation preventing device 30 in accordance with the present invention. Referring to Fig. 9, a fluid displacement apparatus 4S is similar to fluid displacement apparatuses 10 and 40 except for rotation preventing device DC0 I 126WO.1 99- 7-27; 0:26 ;S SPRUSON ;0270245335 15/ 0270245335 Referring to Figs. 9 and 10, rotation preventing device 30 includes orbiting race 24, fixed race 23, a fixed ring 22, and an orbiting ring 21 sandwiched between orbiting race 23 and fixed race 24. Rotation preventing device 30 also includes a plurality of hollow portions and 26, formed by orbiting race 23, fixed race 24, fixed ring 22 and orbiting ring 21, that accommodate balls 3. Hollow portions 25 and 26 are similar to those described above except for the shape of the bottom surface. The bottom surface of hollow portions 25 and 26 serve as rolling surfaces 23a and 24a for balls 3 such, that orbiting race 23 and fixed race 24 are in contact with a plurality of holes within orbiting ring 21 and fixed ring 22. Orbiting ring 21 and fixed ring 22 contact each other at the opposite surface 22a and 21a. Hollow portions 25 and 26 have a depth R3 and R4, respectively. The sum of depth R3 and R4 is about equal to, or slightly greater than, the diameter of balls 3.

As above mentioned, the rotation preventing device, which comprises a ball coupling mechanism and a pair of race members, prolongs operational capacity by decreasing the load to which the rotation preventing device subjected. Further, the arrangement in these embodiments of the present invention reduces the number of balls within the rotation preventing device and results in decreasing cost in assembly. The arrangement may reduce noise and vibration of the fluid displacement apparatus and makes the body of the apparatus compact by using resin.

Although the present invention has been described in connection with the preferred embodiments, the invention is not limited thereto. Accordingly, the embodiments and features disclosed herein are provided by way of example only. It will be understood by those of ordinary skill in the art that variations and modifications may be made within the scope of this invention as defined by the following claims.

DC01:226409.1

Claims (6)

1. A rotation preventing device for preventing rotation of an orbiting scroll member of a fluid displacement apparatus, said orbiting scroll member having a predetermined orbit radius and a predetermined angular relationship with a fixed scroll member of said fluid displacement apparatus, the device comprising; a pair of annular members connected to said orbiting scroll member and having a plurality of bearing elements, said plurality of bearing elements placed between a pair of said annular members, a pair of said annular members substantially contacting each other at facing surfaces thereof. 0to 2. The rotation preventing device of claim 1, wherein said annular members include a plurality of corresponding concave portions for accommodating said plurality of said bearing elements.

3. The rotation preventing device of claim 2, wherein said corresponding concave portions include a flat surface at a center of a bottom portion.

4. The rotation preventing device of claim 2, wherein a depth of said corresponding concave portions is about equal, or greater than, a diameter of each bearing element. The rotation preventing device of claim 1, wherein at least one of said annular member is made from a resin.

6. The rotation preventing device of claim 1, wherein at least one of said annular member is comprised of an alloy including a material selected from the group .•consisting of aluminum, magnesium, and titanium. .9% 9• o9 99 9

9.o 999 9 9°• [R \LIBLL]08159 doc: VJP

99- 7-27 0 2 6 1)5 Wj gg SPRUSON ;0270245335 18/ 0 270 2453 7. The rotation preventing device of claim 1, wherein at least one of said -annular members is made of ceramic. S. The rotation preventing device of claim 1, wherein said bearing ecment is comprised of an alloy including of a material selected from the group consisting of aluminum, magnesium, and titanium, 9. The rotation preventing device of claim wherein said annular members include a pair of rings and a pair of races coupled to one ead surface of each of said rings, The rotation preventing device of claim 1, wherein said annular members are races. 11. The rotation preventing device of claim 1, wherein said bearing elements are balls, 12. A fluid displacement apparatus, comprising: a housing having a front en d plate; a fixed scroll member attached to said housing, an orbiting member having an end plate from which an annular member extends, said fixed and orbiting members interfitting at a radial offset to establish at least one line contact to separate a fluid outlet from a fluid inlet; a driving mechanism including a rotatable drive shaft connected to said orbiting scroll member to drive said orbiting member in an orbiting motion; ~o a rotation preventing mechanism for preventing the rotation of said orbiting scroU member during orbital motion; and OCV 1'226409.1 *33- 7-27; 0:26 _SPRUSON 0 27 02 45 3 35 1/ 0270245335 first and a second annular members connected to said orbiting scroll member and having a plurality of bearing elements placed between said annular members, said annular -members substantially contacting each other at facing surface thereof 13. The fluid displacement apparatus of claim 12, wherein said annular S members include a plurality of corresponding concave portions each opposing pair of said portions receiving one of said plurality of said bearing elements. 14. Th e fluid displacement apparatus of claim 13, wherein said corresponding concave portions have a bottom portion, and include a flat surface at a center of said bottom portion, 15. The fluid displacement apparatus of claim 13, wherein a depth of said corresponding concave portions is greater than or equal to a diameter of said bearing elements. 16. The fluid displacemnent appAratus of claim 13, wherein at least one of said annular members is made from resin. .17. The fluid displacement apparatus of claim 12, wherein at least one of said annular members is comprised of an alloy including a material selected from the group consisting of aluminum, magnesium, and titanium. 018. The fluid displacement apparatus of claim 12, wherein at least one of said annular member is made from ceramic. 19. The fluid displacement apparatus of claim 12, wherein said bearing 0--20 element is comprised of an alloy including a material selected from the group consisting of aluminum, magnesium, and titanium. DCOI :226409.1 20/ .99- 7-27 0 25 6 7 0 SPRUSON ;0270245335 20/ 0270245335 The fluid displacement apparatus of claim 12, wherein said annular -members includes a pair of rings and a pair of races coupled to one end surface of each of said -rings, 21. members are races. 22. The fluid displacement apparatus of claim 12, wherein said annular The fluid displacement apparatu of claim L2, wherein~ each bearing element is a ball. 9. 99 9* 9 4 0 9 99 9 0**9 .4.4 4* *0 0 .9 9 9. 9 999* 9 0*99 09 99 9 9 9 DCOI :22W49.1 23. A rotation preventing device for preventing rotation of an orbiting scroll member of a fluid displacement apparatus, the device substantially as hereinbefore described with reference to Figs. 1 to 4; Figs. 5 to 8; or Figs. 9 and 10 of the accompanying drawings. 24. A fluid displacement apparatus substantially as hereinbefore described with reference to Figs. 1 to 4; Figs. 5 to 8; or Figs. 9 and 10 of the accompanying drawings. Dated 30 July, 1999 Sanden Corporation Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:\LIBLL]08159 doc:VJP