Axial compliance/sealing means for improved radial sealing for scroll apparatus and scroll apparatus incorporating the same

Axial compliance/sealing means are provided for scroll-type apparatus. These means comprise seal elements associated with the involute wraps which are urged by an axial force to make sealing contact with the end plates of the opposing scroll members. A two-sided channel open to the centerline of the apparatus is cut in the contacting end of each wrap; and within the channel is positioned a seal element for making sealing contact with the surface of the end plate of the opposing or complementary scroll member. The seal element is compressively loaded toward the back of the channel and axially loaded toward the opposing end plate. The use of the axial compliance/sealing means allows the contacting surfaces through which radial sealing is effected to be machined to conventional accuracy, provides automatic compensation for temperature differentials within the apparatus as well as for any uneven wear of the scroll members, and permits the use of machining and fabrication techniques which are relatively low in cost.

This invention relates to scroll-type apparatus and more particularly to 
scroll-type apparatus having axial and radial compliance/sealing means 
which materially reduce the problems of constructing the scroll-type 
apparatus and which enhance its extended operation. 
There is known in the art a class of devices generally referred to as 
"scroll" pumps, compressors and expanders wherein two interfitting 
spiroidal or involute spiral elements of like pitch are mounted on 
separate end plates. These spiral elements are angularly and radially 
offset to contact one another along at least one pair of line contacts 
such as between spiral curved surfaces. A pair of line contacts will lie 
approximately upon one radius drawn outwardly from the central region of 
the scrolls. The fluid volume so formed therefore extends all the way 
around the central region of the scrolls. In certain special cases the 
pocket or fluid volume will not extend the full 360.degree. but because of 
special porting arrangements will subtend a smaller angle about the 
central region of the scrolls. The pockets define fluid volumes, the 
angular position of which varies with relative orbiting of the spiral 
centers; and all pockets maintain the same relative angular position. As 
the contact lines shift along the scroll surfaces, the pockets thus formed 
experience a change in volume. The resulting zones of lowest and highest 
pressures are connected to fluid ports. 
An early patent to Creux (U.S. Pat. No. 801,182) describes this general 
type of device. Among subsequent patents which have disclosed scroll 
compressors and pumps are U.S. Pat. Nos. 1,376,291, 2,475,247, 2,494,100, 
2,809,779, 2,841,089, 3,560,119, 3,600,114, 3,802,809, and 3,817,664 and 
British Pat. No. 486,192. 
Although the concept of a scroll-type apparatus has been known for some 
time and has been recognized as having some distinct advantages, the 
scroll-type apparatus of the above-identified prior art has not been 
commercially successful, primarily because of sealing and wearing problems 
which have placed severe limitations on the efficiencies, operating life, 
and pressure ratios attainable. Such sealing and wearing problems are of 
both radial and tangential types. Thus, effective axial contacting must be 
realized between the ends of the involute spiral elements and the end 
plate surfaces of the scroll members which they contact to seal against 
radial leakage and achieve effective radial sealing; and in some types of 
scroll apparatus effective radial contacting with minimum wear must be 
attained along the moving line contacts made between the involute spiral 
elements to seal against tangential leakage. 
Early approaches to the attainment of acceptable radial sealing in prior 
art apparatus included machining the components (wraps and end plates) to 
accurate shapes for fitting with very small tolerances and using one or 
more mechanical axial constraints, e.g., bolts to force the surfaces into 
contact. The more recent prior art teaches sealing through the use of a 
compliant fixed scroll member (U.S. Pat. No. 3,874,827) or the use of a 
pressurized fluid (with or without springs to provide an augmenting axial 
force) to urge the scroll members into axial contact (U.S. Pat. Nos. 
3,600,114, 3,817,664, 3,884,599, and 3,924,977). The recent prior art also 
includes improved radial sealing means, particularly suited for 
scroll-type compressors or expanders operating at high pressures, in which 
all of the forces required to achieve efficient axial load carrying are 
pneumatic forces provided by pressurizing all or a selected portion of the 
apparatus housing. Thus, the housing defines with a surface of the 
orbiting scroll member a pressurizable chamber whereby the fluid pressure 
within that chamber forces the orbiting scroll into continued axial 
contact relationship with the fixed scroll member. 
The substitution of a compliant fixed scroll member with axial forces 
applied thereto or of pneumatic forces acting upon the orbiting scroll for 
the use of bolts to force surface contacts have gone a long way to the 
solving of the radial sealing problems in scroll-type apparatus. However, 
these techniques still require very accurate machining of both the 
contacting surfaces, i.e., the surfaces of the end plates and the surfaces 
of the involute spiral wrap members. This requirement of accurate 
machining adds materially to the cost of the scroll type apparatus 
manufacture. Moreover, any axial misalignment in the apparatus during 
operating will generally result in uneven wear, thus defeating the 
attainment of the accurate machining. Finally, radial temperature 
gradients within the apparatus give rise to uneven dimensional changes in 
the height of the involute wraps. 
In U.S. Pat. No. 3,994,636 there is disclosed sealing means which permits 
the contacting surfaces to be machined only to conventional accuracy to 
attain acceptable axial contacting and hence efficient radial sealing. In 
this sealing means, a three-sided channel is cut in the tip surface of 
each of the wraps and it is formed to follow the configuration of the 
wrap. Within each channel is placed a compliance/sealing means through 
which the axial contact is effected. Each of the compliance/sealing means 
comprises in combination a seal element seated in the channel and of the 
same involute configuration as the channel and force applying means for 
actuating the seal element to effect the required axial contact. The width 
of the seal element is less than the width of the channel to permit the 
seal element to experience small radial and axial excursions within the 
channel; and the seal element has a contacting surface width which is less 
than the width of the wrap. 
The use of the axial compliance/sealing means of U.S. Pat. No. 3,994,636 
has proved effective in attaining satisfactory radial sealing. However, by 
making certain improvements in the axial compliance/sealing means 
structure disclosed and claimed in U.S. Pat. No. 3,994,636 it is possible 
to reduce the manufacturing cost associated with the radial seal while at 
the same time attaining a better machine finish on the channel surface. It 
is also possible to preload the seal element radially as well as loading 
it axially. 
It is therefore a primary object of this invention to provide an improved 
axial compliance/sealing means for achieving radial sealing of scroll-type 
apparatus. It is another object to provide sealing means of the character 
described which makes it possible to form the actuating member of the 
sealing means by simple fabricating techniques and which reduces the 
manufacturing costs of the scroll members. Yet another object is to 
provide axial sealing means which are so constructed as to be radially 
loaded even during relative motion of the scroll members. 
It is another primary object of this invention to provide improved 
scroll-type apparatus in which the contacting surfaces through which 
radial sealing is realized need be machined only to conventional accuracy. 
It is a further object of this invention to provide scroll-type apparatus 
of the character described which incorporate axial compliance/sealing 
means to effect efficient radial sealing during prolonged operation even 
though some radial temperature gradients are experienced within the 
apparatus and uneven wear of the contacting surfaces, through which radial 
sealing is attained, is brought about. A further object of this invention 
is to provide axial compliance/sealing means of the character described 
which may be used with a lubricant or which may be adapted for apparatus 
which must operate without lubricants. 
It is an additional primary object of this invention to provide scroll-type 
apparatus including compressors, expansion engines and pumps which may be 
constructed at costs somewhat less than heretofore possible. 
Other objects of the invention will in part be obvious and will in part be 
apparent hereinafter. 
The invention accordingly comprises the features of construction, 
combinations of elements, and arrangement of parts which will be 
exemplified in the constructions hereinafter set forth, and the scope of 
the invention will be indicated in the claims. 
According to one aspect of this invention there is provided a scroll member 
suitable for constructing a scroll apparatus, comprising in combination an 
end plate; an involute wrap attached to the end plate and having a 
two-sided channel cut along essentially the length of the surface of the 
wrap, the channel opening toward the centerline of the scroll element and 
having a back surface and a seating surface; a seal element positioned in 
the channel, compressively loaded toward the back surface of the channel 
and extending throughout essentially the entire length thereof, the seal 
element being suitable for making sealing contact with the surface of an 
end plate of a complementary scroll member forming part of the scroll 
apparatus; and seal spring means formed as a continuous strip engageable 
with the back surface of the channel and having a plurality of spring 
members configured to exert an axial force on the seal element in the 
direction of the end plate of the complementary scroll member. 
According to another aspect of this invention there is provided a positive 
fluid displacement apparatus, comprising in combination a stationary 
scroll member having a stationary end plate and a stationary involute wrap 
having a two-sided channel cut along essentially the length of its 
contacting end surface, the channel opening toward the centerline of the 
apparatus and having a back surface and a seating surface; an orbiting 
scroll member having an orbiting end plate and an orbiting involute wrap 
having a two-sided channel cut along essentially the length of its 
contacting end surface, the channel opening toward the centerline of said 
apparatus and having a back surface and a seating surface, the stationary 
and the orbiting scroll members being complementary to each other; driving 
means for orbiting the orbiting scroll member relative to the stationary 
scroll member while maintaining the scroll members in a predetermined 
fixed angular relationship, whereby the stationary and the orbiting 
involute wraps define moving fluid pockets of variable volume and zones of 
different fluid pressure; means for providing an axial force to urge the 
stationary involute wrap into axial contact with the orbiting end plate 
and the orbiting involute wrap into axial contact with the stationary end 
plate thereby to achieve radial sealing of the pockets; and 
compliance/sealing means associated with each of the involute wraps, each 
compliance/sealing means comprising, in combination, a seal element 
positioned in the channel, compressively loaded toward the back surface of 
the channel and extending throughout essentially the entire length 
thereof, the seal element being suitable for making sealing contact with 
the surface of the end plate of the complementary scroll member forming 
part of the apparatus; and seal spring means formed as a continuous strip 
engageable with the back surface of the channel and having a plurality of 
spring members configured to exert an axial force on the seal element in 
the direction of the end plate of the complementary scroll member.

Inasmuch as radial sealing within scroll-type apparatus is an essential 
feature of such apparatus and since any axial contacting means must be 
capable of attaining radial sealing, it will be helpful, before describing 
the axial compliance/sealing means of this invention to briefly review the 
problems of radial sealing to understand the role which the axial 
compliance/sealing means of this invention must play in effectively 
sealing off the pockets within the apparatus to obtain efficient operation 
over extended periods of time with little or no maintenance. Since the 
principles of the operation of scroll apparatus have been presented in a 
number of previously issued patents, it is unnecessary to repeat a 
detailed description of the operation of such apparatus in discussing the 
problems faced in attaining effective radial sealing. It is only necessary 
to point out that a scroll-type apparatus operates by moving sealed 
pockets of fluid taken from one region into another region which may be at 
a different pressure. The sealed pockets of fluid are bounded by two 
parallel planes defined by end plates, and by two cylindrical surfaces, 
i.e., wraps, defined by the involute of a circle or other suitably curved 
configuration. The scroll members have parallel axes since in only this 
way can the continuous sealing contact between the plane surface of the 
scroll members be maintained. Movement of the pockets defined between the 
parallel surfaces of the end plates is effected as one cylindrical surface 
(flank of the wrap of the orbiting scroll member) is orbited relative to 
the other cylindrical surface (flank of the wrap of the stationary scroll 
member). In the case of compressors and expanders, the pressures in the 
moving pockets decrease radially outward, a fact which means that there is 
a pressure differential from one pocket to its radially adjacent pocket 
which makes it necessary to provide a sealing contact between the wrap end 
contacting surface and the end plate surface of the complementary or 
opposing scroll member to prevent fluid leakage from the higher- to the 
lower-pressure pockets. Thus, it will be seen that it requires some form 
of axial loading to ensure contact between the wrap end surfaces and end 
plates to achieve radial sealing. 
In the design and construction of scroll-type apparatus tangential sealing 
may also be important. Tangential sealing may be achieved through 
maintaining line contact between the wrap flanks as the orbiting scroll 
member is moved. Since tangential and radial sealing are usually, but not 
always, attained through separate mechanisms, the axial compliance/sealing 
means of this invention may be employed in scroll-type apparatus using 
different tangential sealing techniques. The axial compliance/sealing 
means may also, however, be used in those scroll-type apparatus wherein a 
small clearance is maintained between the flanks of the wraps to minimize 
wear and in liquid pumps wherein tangential sealing is of lesser 
importance than in a compressor, for example. Thus, the axial 
compliance/sealing means of this invention are equally applicable to the 
scroll apparatus of U.S. Pat. Nos. 3,884,599, 3,924,977, 3,994,633, 
3,994,635, 4,065,279, and 4,082,484 and to the scroll apparatus 
incorporating a peripheral drive as described in copending application 
Ser. No. 896,161 as well as to the scroll liquid pumps described in U.S. 
applications Ser. Nos. 807,413 and 807,414. 
FIGS. 1 and 2 are presented to further illustrate the problem of providing 
radial sealing with compliance without the need for the extremely accurate 
machining of contacting surfaces. The cross sectional views of FIGS. 1 and 
2 show only portions of end plates, wrap members and fluid pockets. A 
complete exemplary scroll-type apparatus embodying the sealing/compliance 
means of this invention is shown in FIG. 16 and is described in detail 
below. 
In FIGS. 1 and 2, the stationary scroll member 10 is seen to comprise an 
end plate 11 and a wrap 12. End plate 11 has a centrally located fluid 
port 13. For convenience in discussing the compliance/sealing means of 
this invention and the scroll-type apparatus in which these means are 
incorporated, the apparatus will hereinafter be assumed to be a 
compressor. However, it will be apparent to those skilled in the art that 
the compliance/sealing means are equally applicable to scroll-type 
apparatus used as expansion engines or as pumps. 
In FIGS. 1 and 2 the orbiting scroll member 14 is likewise formed of an end 
plate 15 and an involute wrap 16. In practice, the orbiting scroll member 
may be attached to a drive shaft (not shown) or caused to orbit through 
the use of a suitable peripheral drive mechanism. In operation, the 
orbiting scroll member 15 is driven to describe an orbit while the two 
scroll members are maintained in a fixed angular relationship. In its 
orbiting motion, the orbiting scroll member defines one or more moving 
fluid pockets, i.e., pockets 20-24 in which P.sub.0 &lt;P.sub.1 &lt;P.sub.2 
(FIG. 2). These pockets may be bounded radially by sliding or moving line 
contacts between wraps 12 and 16; or for some applications a small 
clearance may be maintained between the flank wraps (see for example U.S. 
Pat. No. 4,082,484). The fluid is taken through inlet line 25 into the 
peripheral zone 26 surrounding the wraps and from zone 26 it is introduced 
into the pockets and compressed as the pockets become smaller in volume as 
they approach the central pocket 20. Thus, only through effective radial 
sealing can the desired fluid pressures in the various moving pockets be 
maintained. 
In the apparatus of this invention, this radial sealing is achieved through 
the contact of the surface 30 of stationary end plate 11 by the surface 31 
of a seal element 32 seated in orbiting wrap 16 and axially forced against 
surface 30 and through the contact of the surface 33 of orbiting end plate 
15 by the surface 34 of a seal element 35 seated in stationary wrap 12 and 
axially forced against surface 33. It will be appreciated that in FIG. 1, 
which is presented only for the purpose of discussing the general concept 
of radial sealing, the details of the axial compliance/sealing means of 
this invention are not shown. 
FIG. 3 is a cross section through the axial compliance/sealing means 
generally indicated by the numberal 40, associated with the wrap 12 of the 
stationary scroll member 10 and forming sealing contact with surface 33 of 
orbiting end plate 15. Since this sealing means is continuous along 
essentially the entire length of the wrap and since the construction of 
the sealing means associated with the involute wrap 16 of the orbiting 
scroll member 14 is identical to that shown in FIG. 3, this figure may be 
used to illustrate the axial compliance sealing means for both scroll 
members. 
As noted previously, sealing contact is made between surface 34 of seal 
element 35 and end plate surface 33. Seal element 35 is set in a two-sided 
channel 41 cut in the end surface 42 of wrap 12. The channel thus has a 
back surface 43 which is normal to surface 33 of end plate 15 and a 
seating surface 44 which is preferably parallel to surface 33. Channel 41 
opens inwardly toward the centerline of the scroll element. In order to 
ensure continuous sealing throughout the length of the involute wrap while 
at the same time minimizing frictional wear, a seal spring, generally 
indicated by the numeral 45, is provided to compliantly apply an axial 
force on seal element 35, the seal-element being so designed and seal 
spring member being so sized that the seal element always extends slightly 
above wrap surface 42. 
The cutting of channel 41 with one open side achieves several advantages 
over the cutting of a three-sided groove such as shown in U.S. Pat. No. 
3,994,636. For example, this present configuration permits the use of a 
large diameter cutter for machining out the channel which results in lower 
manufacturing costs; and a better machine finish on channel surfaces 43 
and 44 is attained. 
The seal spring 45 is preferably formed as a single continuous element. A 
first embodiment of such an element is illustrated in FIGS. 3-7 and a 
second embodiment in FIGS. 8-11. The seal spring of FIGS. 3-7 is formed by 
stamping and bending. As will be seen in FIGS. 4 and 6, the stamped out 
blank comprises a straight back member 46 and a plurality of arcuate 
spring members 47 centrally joined thereto through necks 48. In shaping 
the seal spring, the arcuate spring members 47 are bent on fold line 49 
toward back member 46 to form a 90.degree. angle; and the arms 47a and 47b 
of arcuate members 47 are bent upward along fold lines 50 and 51 to leave 
a central flat spring seat 52 which rests on seating surface 44 of channel 
41. The required axial force is applied by spring arms 47a and 47b on 
which seal element 35 sits. As will be seen from FIGS. 6 and 7, the degree 
of curvature of the arcuate members preferably increases and their length 
preferably decreases along the length of the seal spring, the curvature 
being greatest and length being shortest at the inboard or central end of 
the involute channel. The actual degrees of curvature and lengths chosen 
for the spring members 47 will depend upon a number of factors and can be 
readily determined when such factors are established. These factors 
include the configuration of the involute wrap, the desired upward force 
to be exerted on seal element 35, the properties of the material from 
which seal element 35 is formed, and the amount of wear that can be 
tolerated. 
The axial force of the seal spring must be at least that which prevents any 
appreciable leakage across the involute wrap end from a pocket of higher 
pressure, e.g., pocket 21 at P.sub.1 to a pocket of lower pressure, e.g., 
pocket 23 at P.sub.2. However, since the seal element 35 experiences some 
motion due to the orbiting of the orbiting scroll member and thus induces 
some motion in the spring seal, the axial force of the seal spring should 
not be of such a magnitude as to give rise to excessive wear of the seal 
element or of the spring seat 52 or to result in the development of 
excessive friction power dissipation. The use of a seal spring which 
operates to develop axial forces, along its entire length, of a magnitude 
which falls within the range specified provides an axial 
compliance/sealing means which has an extended fatigue life and which is 
able to operate many hours under the conditions of dynamic motion which 
are encountered in scroll apparatus. 
The seal springs are formed from materials normally used in making flat 
springs, i.e., materials having a high fatigue limit, high endurance 
strength and high yield strength. Such materials include, but are not 
limited to, phosphor bronze, beryllium copper, spring steel and the like. 
Sheet thicknesses ranging between about 0.004 and 0.020 inch (about 0.01 
and 0.05 cms) are generally preferred for forming the seal spring blanks. 
FIGS. 8-11 illustrate another embodiment of a seal spring suitable for the 
sealing means of this invention. As will be seen from FIG. 8, the 
stamped-out blank 54 is formed as a continuous back member 55 having a 
plurality of frustoconically configured tabs 56 serving as spring members. 
As will be seen in FIGS. 9 and 10, tabs 56 are folded toward back member 
55 along fold line 57, tabs 56 being turned toward each other in the 
curving of channel 41 as seal spring is placed along the length of 
involute wrap 12. As in the case of arcuate members 47 of the seal spring 
of FIGS. 3-7, the shapes of tabs 56 are adjusted along the length of the 
seal spring to take into account the changing degree of curvature of the 
involute wrap from its inboard end to its outboard end. Likewise the 
degree of bending of tabs, i.e., the angle defined between tabs 56 and 
back member 55 (FIG. 10), is adjusted to attain a predetermined axial 
force on seal element 35. The range of the magnitude of such axial force 
is the same as that defined for the first seal spring embodiment. The 
manner in which such axial force is exerted on seal element 35 is shown in 
FIG. 11 wherein the reference numerals are the same as those in FIGS. 
8-10. 
The seal element 35, shown in a planar view in FIG. 12, is in essence a 
spring which is positioned and maintained in channel 41 to be 
compressively loaded toward back surface 43 of the channel. Thus, the seal 
element is radially loaded as well as axially loaded. As will be seen from 
the cross section of the seal element in FIG. 13, it is preferably of a 
rectangular configuration, the flat contacting surface 34 being somewhat 
narrower than seating surface 44 of channel 41 so that when the sealing 
means is assembled as in FIG. 3 or 11, the exposed surface of seal element 
35 does not extend beyond the inner flank surface of the wrap. 
In assembling the axial compliance/sealing means in the channel of the 
scroll members the seal element is torqued in by pushing on the outboard 
end and held in this preloaded condition either by a stop pin 60 which is 
mounted at the outboard end of channel 41 (FIG. 14), or by a compressed 
spring 61 anchored to a pin 62 in the outboard end of channel 41. As will 
be seen in FIG. 2, the seal spring, i.e., back member 46, and seal-element 
35 extend to within a short distance of the inboard end 63 of the involute 
wrap; while channel 41 is cut to the end 63 leaving only a terminal 
channel wall 64. There is thus defined a small free channel volume 65 
which provides relief for the thermal expansion of the seal spring and 
seal element. 
The circumferential preload on the seal element in the channel must be 
sufficient to provide continuous radial preloading between seal element 35 
and back wall 43; but it must be less than that which prohibits free axial 
motion of the seal element up and down in the channel as brought about by 
the axial force exerted by the seal spring and the dynamic motion of the 
end plate of the opposing scroll member. As an example, it has been found 
that a preload force of about three pounds falls within this desired 
range. 
In the axial compliance/sealing means of this invention the seal element in 
the open-sided channel is able to maintain the desired preloading and 
sealing at both the primary surface (end plate) and secondary surface 
(channel back) as a result of the axial and radial spring forces. 
Moreover, the inherent stiffness of the seal element, when supported at 
its periphery, prevents it from moving radially inward out of the channel 
under the friction loading encountered in the scroll apparatus. 
Seal element 35 may be formed of a non-metallic material such as a 
polyimide or of a metallic material such as cast iron, hardened steel, 
chrome-plated steel and the like. The material must possess a degree of 
springiness to allow it to be preloaded in the wrap channel; and it must 
also, of course, exhibit a high predetermined resistance to wear inasmuch 
as it is the surface of the seal element which must continue to make 
moving sealing contact with the end plate of the opposing scroll member. 
It is within the scope of this invention to run the seal dry or with 
lubrication, and in the latter case seal element 35 may have a lubrication 
groove 66 cut in contacting surface 34 as shown in FIG. 13. 
As previously pointed out, the axial compliance/sealing means of this 
invention may be used with many different types of scroll apparatus 
including, but not limited to, the apparatus described in U.S. Pat. Nos. 
3,874,827, 3,884,599, 3,924,977, 3,986,799, 3,994,633, 3,994,635, 
4,065,279, and 4,082,484. The sealing means may also be used in scroll 
apparatus designed exclusively as pumps such as those disclosed and 
claimed in copending applications Ser. Nos. 807,413 and 807,414 filed June 
17, 1977, as well as in scroll apparatus employing peripheral drive means 
such as disclosed and claimed in U.S. Ser. No. 896,161 filed Apr. 14, 
1978. The three mentioned applications are assigned to the same assignee 
as the present application. 
In illustrating the application of the axial compliance/sealing means of 
this invention, the scroll apparatus of U.S. Pat. No. 4,082,484 may be 
taken as exemplary. A longitudinal cross section of such an apparatus is 
shown in FIG. 16 which is described hereinafter, for convenience, as a 
compressor. 
The compressor shown in FIG. 16 is comprised of a stationary scroll member 
70 formed of an end plate 71 and involute wraps 72; an orbiting scroll 
member 73 formed of an end plate 74 and involute wraps 75; a coupling 
member 76, a drive mechanism generally indicated by reference numeral 77; 
crank and shaft assembly means generally indicated by reference numeral 
78; housing 79 including an oil sump 80, cooling fan 81 and cover 82. 
End plate 71 of the stationary scroll member terminates in a peripheral 
ring 85 and an outwardly extending flange 86, these portions of end plate 
71 forming a part of the apparatus housing. End plate 71 also has a 
central stub extension 87 defining a high-pressure fluid passage 88 in 
communication with high-pressure fluid pocket 89 defined by wraps 72 and 
75. This central stub extension 87 is internally threaded at 90 for 
engagement with a high-pressure fluid conduit (not shown). End plate 71 
also has a peripherally positioned stub extension 91 defining a 
low-pressure fluid passage 92 communicating with the low-pressure 
peripheral fluid pocket 93 and being threaded at 94 for engagement with a 
low-pressure fluid conduit (not shown). 
Radial sealing of the fluid pockets 89, 93 and intermediate-pressure 
pockets 95, 96, and 97, is achieved across end surfaces 100 of stationary 
scroll member wraps 72 and the inner surface 101 of orbiting scroll end 
plate 74 and across end surfaces 102 of orbiting scroll member wraps 75 
and the inner surface 103 of stationary scroll end plate 71. This is 
accomplished through the use of the axial compliance/sealing means of this 
invention, only channel 106 (equivalent to channel 41 of FIG. 3) and a 
seal element 107 (equivalent to seal element 35 of FIG. 3) being shown. 
The diameter of end plate 74 of the orbiting scroll member is sufficiently 
great such that it always extends beyond the inner edge of flange 86, thus 
permitting the placement of an oil seal ring 115 between end plate 74 and 
flange 86 to seal off the fluid pockets from the remainder of the 
apparatus. This in turn allows the drive mechanism and bearings to be 
oil-lubricated while maintaining the working fluid substantially free from 
any liquid, since it is the purpose of the oil seal ring to prevent the 
passage of any lubricating oil in the volume surrounding the orbiting 
scroll member from entering the moving fluid pockets. 
The housing, generally indicated by the reference numeral 79, is comprised 
of ring extension 85 of the stationary scroll member, flange 86, and main 
housing section 120 which is flanged at 121 and is integral with a lower 
oil sump housing 122. The housing is attached and sealed to the scroll 
members through flanges 86 and 121 by a plurality of bolts 123 using an 
o-ring seal 124. 
In operation, the two scroll members must be maintained in a fixed angular 
relationship, and this is done through the use of coupling member 76. The 
coupling member illustrated in the apparatus embodiment of FIG. 16 is 
essentially the same as the coupling member described in U.S. Pat. No. 
3,994,633 (see FIG. 14 of that patent and the detailed description 
thereof). Thus, as seen in FIG. 16, the coupling member comprises a ring 
128 having oppositely disposed keys 129 on one side thereof slidingly 
engaging keyways 130 in the inner surface of housing flange 121. A second 
pair of keys (not shown) are oppositely disposed on the other side of 
coupling ring 128 to slidingly engage keyways in the end-plate of the 
orbiting scroll member. It is also, of course, within the scope of this 
invention to use any other suitable coupling means such as that described 
and claimed in copending application Ser. No. 722,713, filed Sept. 13, 
1976, in the name of John E. McCullough and assigned to the same assignee. 
Orbiting scroll member 73 has a stub shaft 135 affixed to or integral with 
end plate 74. The orbiting scroll is driven by a motor (not shown) 
external of the housing and engageable with compressor shaft 136 extending 
into the housing through an oil seal 137 and terminating in a crank plate 
138 which may be affixed to or integral with shaft 136. Shaft 136 is 
mounted in the housing through shaft bearing 139 and crank bearing 140. 
The driving means of the scroll apparatus of FIG. 16 is designed to use a 
fixed throw crank drive mechanism and to operate with a small clearance 
between the flanks of the wraps of the scroll members. Since this drive 
mechanism is not a part of the present invention it is not necessary to 
describe it in detail. Rather, reference may be had to the detailed 
description of the driving means in U.S. Pat. No. 4,082,484 incorporated 
herein by reference. The remaining description of FIG. 16 will therefore 
not present in great detail the driving means of the compressor shown. 
As will be seen in FIG. 16, the orbiting scroll member is affixed to drive 
shaft 136 through bearing mount 141 having a counterweight 142 for the 
purpose of balancing the centrifugal force of the orbiting scroll member. 
Bearing mount 141 engages the stub shaft 135 through needle bearing 143 
held in place by a snap ring. Interposed between bearing mount 141 and the 
outer surface of the end plate of orbiting scroll member 73 is a thrust 
face bearing 145 which acts as the axial force-applying means to urge the 
end plates and wrap ends of the two scroll members together to realize the 
desired axial sealing through the axial compliance/sealing means. Thrust 
face bearing 145 carries the load from orbiting scroll member 73 through 
the crank bearing 140 and subsequently to the housing. Main shaft 136, 
crank plate 138, bearing mount 141 and counterweight 142 make up the 
adjustable fixed-throw drive meachanism of the scroll machinery. 
As noted above with regard to the general description of the apparatus 
illustrated in FIG. 16, there is provided an oil sump 80 in lower section 
122 of the apparatus housing. The lubricating oil 149 from sump 80 is 
delivered to coupling member 76 and to the various shaft and drive 
bearings within housing 79 by means of one or more oil fingers 150 affixed 
to the coupling member. These oil fingers are of a length such that they 
are periodically dipped into oil 149 and then raised to fling the oil 
upward within the housing for circulation and return into the oil sump. An 
oil passage 151 is provided to conduct some of the oil flung directly into 
housing cavity 152, which surrounds the crank plate and bearing mount, to 
shaft bearing 139. 
In the apparatus embodiment of FIG. 16 means are provided to air cool the 
compressor housing, and through the housing to air cool the elements of 
the compressor and the circulating lubricating oil. An air duct 155, 
terminating in a duct cover 156, is mounted around the apparatus housing 
and supported on the drive end of a plurality of housing fin member 157. 
Cooling air is circulated through the air duct 155 by means of fan 81 
which comprises a plurality of fan blades 158 mounted between the outer, 
belt-engaging rim 159 and the inner shaft engaging ring 160 of a pulley 
161. Pulley 161 is affixed to main shaft 136 through a key 162 engageable 
with keyway 163 in shaft 136. Duct cover 156 is affixed to the scroll 
member end of the housing fin members 157, and it terminates short of 
covering the scroll member end in order to leave a series of air discharge 
openings 164 so that air drawn in by fan 81 is circulated over the 
apparatus housing from drive end to scroll member end and discharged 
through openings 164. 
Through the use of the axial compliance/sealing means of this invention in 
scroll apparatus to make sealing contact between the involute wraps and 
their opposing end plates it is possible to achieve efficient radial 
sealing through the entire length of each wrap even though there may exist 
temperature gradients and some uneven wearing of the end plate surfaces. 
Thus, effective sealing and efficient operation is possible for 
scroll-apparatus incorporating the axial compliance/sealing means of this 
invention. This advantageous operation is obtained at a low cost since the 
machining of the seal channels, the formation of the seal springs and the 
manufacture and installation of the seal elements are all accomplished 
using readily available machining equipment and relatively simple 
fabrication techniques. 
It will thus be seen that the objects set forth above, among those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in the above constructions without 
departing from the scope of the invention, it is intended that all matter 
contained in the above description or shown in the accompanying drawings 
shall be interpreted as illustrative and not in a limiting sense.