TECHNICAL FIELD

[0001] This disclosure relates to the technical field of co-rotating scroll compressors.

BACKGROUND

[0002] Scroll compressors are widely used in refrigerant compression applications including variable refrigerant flow (VRF) systems. A co-rotating scroll compressor includes a driver scroll and an idler scroll and both the driver scroll and the idler scroll have involute sections on one side and shaft sections on respective opposite sides thereof. The center of each involute is on the center of its respective shaft section. The driver scroll may have a long shaft, and the idler scroll may have a shorter shaft or bearing hub for a shaft. In some implementations, the driver scroll is in the center of the compressor, that is, it is aligned with the central axis or centerline of the compressor, and its rotation is powered by motor components including a rotor and a stator. The idler scroll may be positioned in-line, but an orbit radius offset from the driver scroll. An Oldham coupling is disposed directly between the driver scroll land the idler scroll. In general, the driver scroll rotates the Oldham coupling, and the coupling then rotates the idler scroll. While both scrolls rotate, the relative motion between each may be an orbiting motion. Therefore, one involute will orbit with respect to the other involute.

SUMMARY

[0003] Some implementations include arrangements and techniques for a compressor, which may include a cylindrical housing, a lower cap housing engaging with the cylindrical housing, a main shaft disposed along a main axis, a driver scroll having an axis aligned with the main axis and having a spiral involute, an idler scroll having an axis offset from the main axis and having a spiral involute disposed on an idler scroll plate that is intermeshed with the spiral involute of the driver scroll, an Oldham coupling disposed between the driver scroll and idler scroll, an idler scroll shaft hub fixed to the lower cap having an axis aligned with the idler scroll axis, a hub of the idler scroll is disposed on the idler scroll shaft hub fixed to the lower cap, and two arc structures disposed opposite one another on the idler scroll plate. [0004] Further, some implementations include arrangements and techniques for two arc structures disposed opposite one another on the idler scroll plate each having internal oil passages.

BRIEF DESCRIPTION OF THE DRAWINGS [0005] The detailed description is set forth with reference to the accompanying figures. The use of the same reference numbers in different figures indicates similar or identical items or features.

[0006] FIG. 1 illustrates an example of a cross-sectional view of a scroll compressor according to some implementations.

[0007] FIG. 2 illustrates an example of a cross-sectional view of a lower portion of a scroll compressor according to some implementations.

[0008] FIG. 3 illustrates an example of an isometric view of a cross-section of a lower portion of a scroll compressor according to some implementations.

[0009] FIG. 4 illustrates an example of a top view of a cross-section of a lower portion of a compressor according to some implementations.

[0010] FIG. 5 illustrates an example of a top view of an idler scroll according to some implementations .

[0011] FIG. 6 illustrates an example of a perspective view of an idler scroll according to some implementations.

[0012] FIG. 7 illustrates an example of a free-body diagram showing certain forces and moments for components of a comparative example of a compressor according to some implementations .

[0013] FIG. 8 illustrates an example of a free-body diagram showing forces and moments for components of a compressor according to some implementations.

[0014] FIG. 9 illustrates an example of a top view of a cross-section of a lower portion of a compressor according to some implementations.

[0015] FIG. 10 illustrates an example of a cross-sectional view of a lower portion of a scroll compressor according to some implementations.

[0016] FIG. 11 illustrates an example of a top view of a cross-section of a lower portion of a compressor according to some implementations.

[0017] FIG. 12 illustrates an example of a free-body diagram showing certain forces and moments for components of an example of a compressor according to some implementations. [0018] FIG. 13 illustrates an example of a cross-sectional view of a lower portion of a scroll compressor according to some implementations.

[0019] FIG. 14 illustrates an example of an isometric view of a cross-section of a lower portion of a scroll compressor according to some implementations.

DESCRIPTION OF THE EMBODIMENTS

[0020] The respective involutes of the driver scroll and idler scroll fit together as an intermeshing pair of spiral involutes that form crescent shaped pockets of refrigerant gas during operation. In general, during operation, suction gas enters the compressor and then enters an outside area of the scroll pair. The pockets reduce in volume as the orbiting motion occurs, and this compresses the gas to a higher pressure. In some implementations, near the center section, the compression pockets reach a discharge port in the driver scroll and the high pressure gas exits through this port. In some implementations, the compressor is a “high side” design, where suction gas enters directly into the compression chamber and most of the volume inside the compressor housing is at discharge pressure.

[0021] A challenging thrust force scroll compressors contend with is the contact between the idler scroll and the driver scroll. The scroll involute tips of the driver scroll and the idler scroll may contact one another’s involute floor. For example, applied forces to push the driver scroll and the idler scroll together is a combination of discharge pressure (Pd) times a given area, and a compressed suction or intermediate pressure (Pi) times a different given area. This may be referred to as axial compliance, which creates an optimum thrust force for essentially the entire operating envelope of the scroll compressor.

[0022] In some implementations, the scroll involutes are a smaller enclosed diameter (than the outer diameter of the plate) and therefore stability of the scroll set may be a significant challenge because of the developed gas force, which may be tangential (Ftg) or a horizontal component. During operation, the horizontal force Ftg becomes an overturning moment in both the idler and driver scrolls. In some examples, to address this tangential gas force, Ftg two arc structures, which may be part of the idler scroll, may be machined exactly the same height as the height of the involute of the idler scroll; and therefore may make the same contact with the driver scroll plate floor at a greater radius than the involute. Additionally, in some implementations the arc structures may be part of the driver scroll and may be machined exactly the same height as the height of the involute of the driver scroll; and therefore may make the same contact with the idler scroll plate floor at a greater radius than the involute. Accordingly, as explained below, the two arc structures of the idler scroll provide stability during operation. [0023] In some implementations of scroll compressor technology, the tangential gas force Ftg does not rotate with the 360 ° compression crank angle. The tangential gas force Ftg may change magnitude, like in compressors having a fixed scroll intermeshed with an orbiting scroll, but the tangential gas force Ftg may essentially be in a fixed location with respect to the housing. Since the Ftg force has a high peak value, stabilizing arc structure support sections are located on one of the two scrolls, such as the idler scroll, and the top surfaces of the arc section structure support sections may be in the same plane as the involute tip and/or floor planes of the other scroll (e.g., driver scroll).

[0024] Fig. 1 illustrates an example of a cross-sectional view of a scroll compressor according to some implementations. The body or housing of the compressor 1 may include an upper cap 2, center shell 4, and lower cap or base 6. These components may be press fit together, as shown in portions 12 and 14. The upper cap 2, center shell 4, and lower cap 6 may have generally circular profiles. The lower cap 6 may essentially be bowl-shaped having vertical extending edges or rims that are essentially parallel to the driver scroll axis 96, which is a main axis or centerline of driver scroll 50. The lower cap 6 may have an open end or face into which components of the compressor are assembled or disposed that may include, for example, components of the compression mechanism or compression unit, such as the driver scroll 50 and the idler scroll 80 and associated components. The center shell 4 may essentially be cylindrical having an axis parallel to the driver scroll axis 96 and may be concentric to the bore(s) of the one or more bearings on the main shaft or driver scroll shaft 20, such as the main bearing 24. The center shell 4 may have essentially a cylindrical shape with essentially a hollow opening with open top and bottom ends and may be referred to as a “case” and may be composed of sheet met or steel tubing or the like. Further, the upper cap 2 may essentially be a bowl-shaped having vertical edges or rims that are essentially parallel to the driver scroll axis 96. The lower cap 6 has an open end or face which houses components of the compressor once pressed in place during assembly. Further, in some examples, the upper cap 2, center shell 4, and lower cap 6 may be made of low carbon steel and the scroll compressor 1 may be hermetically sealed from the ambient surroundings, but the techniques described herein may also be applied to a semi-hermetic scroll design, without loss in performance. As shown, a hermetic terminal 40 may be disposed in the center shell 4 or alternatively in the upper cap 2. [0025] In some implementations, the entire compressor chamber above the main frame 26, such as the high chamber 28, contains high-pressure discharge gas, the motor components (e.g., motor stator 16 and motor rotor 18), and the upper bearing or outboard bearing 22 assembly. This chamber may also contain the oil sump or reservoir 42, which may essentially be between the main frame 26 and the motor components (e.g., motor stator 16 and motor rotor 18). The chamber below the main frame 26 may contain low pressure suction gas, the compression mechanisms (e.g., driver scroll 50 and idler scroll 80) one or more radial compliance features (e.g., the shaft pin with a drive flat at an angle of Q, with respect to the idler scroll coordinate axis, a corresponding slider block 264, and the idler scroll bearing 94 and idler shaft hub 260 (described below)), and may contain some of the oil in the compressor due to natural leakage through the bearings. In some implementations, a shaft seal 44 is disposed around the driver scroll shaft (main shaft) 20 to seal the main frame 26.

[0026] Further, an upper bearing plate 32 may be disposed with a portion around the upper bearing 22 fanning upward and out toward the upper cap 2. The upper bearing plate 32 may include apertures such as a first set of apertures 38 and a second set of apertures 36. An oil separator dome 34 may also be disposed essentially in the upper cap 2 and above the upper bearing plate 32. In some implementations, the oil separator dome 34 may contact or be connected to the upper bearing plate 32. For example, the discharge gas that exits the driver scroll 50, may contain both gas and entrapped oil. The oil separator dome 34 may reverse the discharge flow and the mixture may exit through the first set of apertures 38, in a downward direction. Since the discharge fitting 10 is the exit for compressed gas from the compressor, the downward flow direction of the fluid is reversed; and flows through the second set of apertures 36 to reach the discharge fitting. Because of the reverse flow direction between the first set of apertures 38 and the second set of apertures 36, most of the entrapped oil in the fluid may be separated from the gas.

[0027] A suction inlet 8 may be disposed in the lower cap 6 to suction a refrigerant gas or or a mixture of liquid and gas and a discharge fitting 10 may be disposed in an upper cap 2. In the example shown in Fig. 1 the refrigerant is suctioned directly into the compression chambers and two pockets may be simultaneously formed by the intermeshing of involutes of the driver scroll 50 and idler scroll 80, and most of the interior of the lower housing is at a suction pressure, which may be known as a “low side” of the co-rotating scroll compressor.

[0028] A driver scroll shaft 20 is aligned with the driver scroll axis 96 and, as mentioned above, may be supported by at least a main bearing 24 and the upper bearing 22, such that the driver scroll axis 96 may be rotated up to very high speeds by the rotor 18, operating inside stator 16. The lower bearing or idler scroll bearing 94 may be disposed around an idler shaft hub 260. Further, the main frame 26 may be press fit inside center shell 4. Since the main bearing 24 is concentric with the main frame pressing diameter, the driver scroll shaft 20 will then be aligned concentrically with the stator 16. Upon operation, the stator 16 imparts a magnetic field such that the rotor 18 will spin and produce high power for compressing the gas in the compression unit, e.g., compression pockets of gas formed by the intermeshing of the spiral involute of the driver scroll 50 and the spiral involute of the idler scroll 80 upon operation. In some implementations, the motor (e.g., rotor 18 and stator 16) may contain a special winding design for the stator 16, as well as a rotor 18 with permanent magnets.

[0029] As shown in Fig. 1 and discussed in further detail below, a seal plate 60 may be disposed on top of the driver scroll plate 52 in some implementations. An Oldham coupling 70 may be disposed between the driver scroll 50 and the idler scroll 80 and a thrust plate 66 may be disposed below the idler scroll 80 in some implementations. Further, in some examples, the seal plate 60 is attached to the thrust plate 66 by bolts 62, such as four equally spaced shoulder blots. Additionally, the compressor 1 may include an oil supply tube 92 that supplies discharge pressure oil from the high side above the main frame 26.

[0030] Additionally, in some implementations, two or more arc structures 86 may be disposed around respective arc sections of the idler scroll plate 82. In other implementations, the arc structures 86 may be disposed around respective arc sections of the driver scroll plate 52. The arc structures 86 will be described in more detail below.

[0031] Fig. 2 illustrates an example of a cross-sectional view of a lower portion of a scroll compressor according to some implementations. As shown in Fig. 2, the compression mechanisms, which may include at least the driver scroll 50 and the idler scroll 80 are disposed below the main frame 26. The driver scroll 50 includes a spiral involute 54 extending downward from a driver scroll involute floor 53, which is a bottom surface or a lower surface of the driver scroll plate 52. The spiral involute 84 of the idler scroll 80 extend upwards from an idler scroll involute floor 81, which is a top surface or upper surface of the idler scroll plate 82. The spiral involute 84 intermeshes with the spiral involute 54 of the driver scroll 50. As mentioned, the driver scroll 50 axis is on the driver scroll axis 96 of the compressor and in some implementations is aligned with at least the upper bearing 22, stator 16, rotor, 18 and main bearing 24. According to some examples, the idler scroll axis 98 is offset from the driver scroll axis 96 (as shown in Fig. 1) and may be disposed at a distance equal to the orbit radius of the spiral involute 84 of the idler scroll and the spiral involute 54 of the driver scroll 50. [0032] Additionally, in some implementations, two or more arc structures 86 may be disposed around respective arc sections or portions of the essentially circular or round idler scroll plate 82 of the idler scroll 80 and may extend upward toward the driver scroll plate 52. Further, in some implementations, two or more arc structures 86 may be disposed around respective arc sections or portions of the essentially circular or round driver scroll plate 52 of the driver scroll 50 and may extend downward toward the idler scroll plate 82. The arc structures 86 will be described in more detail below.

[0033] The compressor 1 may also include a discharge port 202 or hole disposed in the driver scroll 50 for discharging compressed gas. In some implementations, the main bearing 24 is disposed below the shaft seal 44 and above a thrust washer 212 and the driver scroll 50 load may be primarily carried by the main bearing 24. The thrust washer 212 may be disposed between the driver scroll plate 52 and the main frame 26.

[0034] In some implementations and as shown in Fig. 2, an Oldham coupling 70 may be disposed directly between each scroll member (e.g., the driver scroll 50 and the idler scroll 80) and may rest on the idler scroll plate 82. The axis keys of the Oldham coupling 70 may be engaged between the driver scroll 50 and the idler scroll 80 and, in general, as the driver scroll shaft 20 rotates, the driver scroll 50 rotates the Oldham coupling 70, and the Oldham coupling 70 then rotates the idler scroll 80. The Oldham 70 coupling transfers motion from the driver scroll 50 to the idler scroll 80. Accordingly, during operation, while the driver scroll 50 and the idler scroll 80 rotate, the relative motion between each is a circular orbiting motion. Therefore, during operation one involute will orbit with respect to the other involute.

[0035] In some implementations, the idler scroll 80 includes an idler scroll hub 256, that is essentially cylindrical and having an open bottom, and extends in a downward direction from a bottom surface (or lower surface) 83 of the idler scroll plate 82. The idler scroll hub5may be disposed around the idler scroll bearing 94. Further, the idler scroll hub 256 and the idler scroll bearing 94 may be aligned with the offset idler scroll axis 98. In some implementations, the idler scroll 80 load is primarily carried by the idler scroll bearing 94, which may be pressed into the idler scroll hub 256 and may rotate around the essentially stationary slider block 264. The slider block 264 serves as a compliant shaft journal and has a drive flat (discussed below) that is positioned with respect to an idler axis coordinate, at a drive angle Q, which effectively adds adequate flank contact force from the Ftg (tangential gas) vector to minimize leakage. [0036] As is discussed in further detail below, the idler scroll bearing 94 and a crown on the slider block 264 drive flat are lubricated with oil. The slider block 264, in some implementations may be a sintered, hardened, and ground component, which forms a journal for the idler scroll bearing 94. Fig. 2 further shows that in some examples, a lower or base portion of an idler shaft hub 260 may be welded, by resistance welding, for example, to the lower cap 6 and may have one or more protrusions 258 extending downward to be welded. In some implementations, the idler scroll hub 256, slider block 264, and idler scroll bearing 94 are each essentially aligned with the idler shaft hub 260. Further, a slider block seal 262 may be disposed at a lower portion of the slider block 264 and may form a seal at an upper surface of the base portion of the idler shaft hub 260. The slider block seal 262 may control an amount of oil that passes into the low side of the compressor as well as define a stabilizing load of the slider block 264 against the idler shaft hub 260.

[0037] Also, in some implementations, a lubricant, such as oil, may be supplied to the lower portion of the compressor 1 by an oil supply tube 92 that may be sealed with a seal 210 into the main frame 26. Accordingly, an oil supply tube 92 may supply oil pressurized by discharge gas to an oil supply tube inlet 270 that may be sealed at the oil supply tube inlet 270 by a seal 271. Drilled and otherwise created in the idler shaft hub 260 may be an oil passage 272, which may include a radially extending oil passage 282 and an axially extending oil passage 284 that intersect each other in the base portion 290 of the idler shaft hub 260. As shown, one end of the radially extending oil passage 282 connects with the oil supply tube 92. The axially extending oil passage 284 may extend upward through a top surface 286 of the idler shaft hub 260 and may open to a clearance or gap 292 between the idler shaft hub 260 and the slider block 264.

[0038] In some examples, an axially extending oil metering passage 274 may be drilled or otherwise created through a top portion of the slider block 264. A lower end of the oil metering passage 274 may be open to and intersect with the clearance or gap 292. A top end of the oil metering passage 274 may be open to and intersect with a clearance or gap 1305 between the top surface 1304 of the slider block 264 and a portion 1303 of the bottom surface 83 of the idler scroll plate 82 within the idler scroll hub 256. The oil metering passage 274 may be a passage for oil to pass through.

[0039] Further, in some implementations a bump or rounded protrusion 1334 is disposed or extends from the top surface 1304 of the slider block 264. Also, in some examples, the rounded protrusion 1334 is aligned with the axis of the idler shaft hub 260. The rounded protrusion 1334 may contact the portion 1303 of bottom surface 83.

[0040] Accordingly, in some implementations, oil may pass through the oil supply tube 92 and into a radially extending oil passage 282 of the idler shaft hub 260. The oil may pass through the axially extending oil passage 284 within the idler shaft hub 260 into a clearance or gap 292 between the idler shaft hub 260 and the slider block 264. Some oil may then continue through the oil metering passage 274 and into a clearance or gap 1305 between the top surface 1304 of the slider block 264 and a portion 1303 of the bottom surface 83 of the idler scroll plate 82.

[0041] According to some implementations, discharge pressure oil may be supplied underneath the idler scroll hub 256; such that the idler scroll hub 256 becomes similar to a rotating piston. This is because, in some examples, the idler shaft hub 260 and the slider block 264 are essentially a non-rotating piston, and the idler scroll bearing 94 and idler scroll hub 256 are essentially a rotating cylinder for the stationary piston. In some implementations, both the driver scroll 50 and the idler scroll 80 have oil pressurized by discharge pressure applied to them, except the driver scroll 50 force will may have discharge pressure gas v. the idler scroll 80 with discharge pressure oil. Therefore, this implementation may apply the optimum axial gas force to contain the scroll compression, as well as effectively cancel the downward force of the driver scroll. The oil supply tube 92 is one example for conveying the pressurized oil. [0042] With respect to axial compliance, because the driver scroll shaft 20 is essentially located in the high side of the compressor, a downward force of discharge pressure (Pd) times the area of the driver scroll shaft 20 diameter is produced. Therefore, the diameter of the driver scroll shaft 20 is important to the axial compliant force, as well as the strength and deflection considerations. The discharge pressure force component for axial compliance may be accomplished by specifying the diameter of the driver scroll shaft 20. The diameter of the driver scroll shaft 20 may be selected for optimum load carrying capability as well as the associated journal bearing, and the adequate hydrodynamic oil film. Therefore, the piston diameter effect of discharge pressure force is essentially a result of the shaft bearing selection. For example, a driver scroll shaft 20 diameter of 28mm for a compressor capability of lOhp. Additionally, to maintain axial compliance, some implementations may include a seal plate 60, which may contain compressed suction intermediate gas pressure, disposed above a top surface (or upper surface) 51 of the driver scroll plate 52, in the low side chamber. The seal plate 60 may have annular grooves or channels 253, 255 disposed in the bottom surface 63 of the seal plate 60 in which corresponding inner seal 252 and outer seal 254 may engage with to form a sealed chamber during operation. Additionally, in some examples, the inner seal 252 and/or the outer seal 254 may be in contact with the top surface 51 of the driver scroll plate 52. For example, pressure inside the annular grooves or channels 253, 255 may push the inner seal 252 and outer seal 254 outward and downward. The downward force may then cause each seal 252, 254 to make contact with the top surface 51 of the driver scroll plate 52. The seal plate 60 may be offset from the driver, and may be rotated by the idler scroll 80. Therefore, the relative motion between the seal plate 60 and driver scroll 50 is an orbiting motion. Further, the inner seal 252 and outer seal 254 may have this same circular orbiting motion, relative to the driver scroll plate 52. In some instances, the seal plate 60 may be attached to a thrust plate 66, by one or more shoulder-bolts 62 (hereinafter “bolts”) and in some examples four equally- spaced bolts 62 are disposed. The body of a bolt 62 may be a precision ground diameter and length. Further, the bolts 62 may be equally spaced in precise positions, and these are carried downward through the driver scroll plate 52 and rigidly into the thrust plate 66. In some examples, the bolts 62 have a precision slip fit through the seal plate 60, as well as the driver scroll plate 52.

[0043] In some examples, between a bottom surface 63 of the seal plate 60 and the top surface 51 of the driver scroll plate 52, there is a specific clearance or gap 280 and this may be accounted for in the overall length of the bolts 62 and this may depend on the length of the bolts 62. This clearance is required such that the seals 252, 254 can extend downward and make contact between the driver scroll plate 52 and the seal plate 60, and the differential pressure across the respective seals 252, 254 may cause this to occur. Further, there may be a clearance or gap between the top surface 51 of the driver scroll plate 52 and the bottom surface 63 of the seal plate 60. Depending on the type of seals, the clearance could be from 120 - 200 micron. In some examples, the seal application is static, because there may not be spinning or orbiting motion between the driver scroll plate 52 and the seal plate 60. In some implementations, the pressure between the inner seal 252 and outer seal 254 is less than the discharge pressure, and higher than suction pressure. Further, in some implementations, the inner seal 252 and outer seal 254 may be a spring loaded face-type. Further, during operation, a back chamber force may be produced between the inner seal 252 and outer seal 254 of the seal plate 60 and the gas pressure inside the back chamber may be higher than outside of an area between the inner seal 252 and outer seal 254, which may be suction pressure Ps. [0044] In some implementations, a thrust plate 66 may be disposed concentric with the driver scroll axis 96. The thrust plate 66 may be disposed underneath the bottom surface 83 of the idler scroll plate 82. Further, corresponding holes for the bolts 62 may be disposed in the thrust plate 66. In some examples, the thrust plate 66 may rotate around the driver scroll axis 96, on its own axis, and offset with respect to the idler scroll 80. Also, as is explained in more detail below, the driver scroll plate 52 may further include one or more radially-aligned and axially- aligned passages (e.g., passages 220, 222, 224) for compressed suction gas, for example. These passages are explained in more detail below. Additionally, the idler scroll 80 may be loaded against and orbit directly between the top of the thrust plate 66 and the driver scroll involute floor 53 of the driver scroll 50.

[0045] Further, extending upwards from the top surface 51 of the driver scroll 50 may be a driver scroll flange structure 230 that may essentially be cylindrical and may surround a portion of the main shaft 20. In some examples, a lower portion of the driver scroll flange structure 230 may be disposed below a top surface 51 of the driver scroll plate 52 in a recess of the top surface 51. Further, an annular seal 231 may be disposed between the lower portion of the driver scroll flange structure 230 and driver scroll plate 52 due to the difference of pressure (e.g., suction pressure). In some implementations, the driver scroll shaft 20 may be connected to the driver scroll flange structure 230 and may be produced or otherwise manufactured as a separate part or component from the driver scroll plate 52. Upon assembly, the driver scroll shaft 20 is concentric with the involute axis of the driver scroll 50. The driver scroll flange structure 230 is embedded into the top surface 51 of the driver scroll 50, and these two diameters actually create a near perfect alignment of the driver scroll shaft 20.

[0046] A by-pass valve cavity 232 may be disposed within the driver scroll flange structure 230 and partially enclosed by the driver scroll flange structure 230 and may be partially enclosed by the driver scroll shaft 20. A discharge port 202 may be in communication with the by-pass valve cavity 232 of the driver scroll flange structure 230. Additionally, in some implementations, one or more reed valves 234 having a bolt or fastener 235 and a valve backer 236 may be disposed within the by-pass valve cavity 232 with the reed portions covering a by pass port 238, which may be a passage or hole, when closed. The by-pass port(s) 238 may be drilled or otherwise created in the driver scroll plate 52 and may be in communication with the by-pass valve cavity 232 and the compression chamber and/or compression pockets within the intermeshed spiral involute 54 of the driver scroll 50 and the spiral involute 84 of the idler scroll 80. [0047] In some implementations, the reed valves 234 are disposed partially over the spiral involute 54 of the driver scroll 50. Further, as shown, the driver scroll flange structure 230 may be concentric with respect to the driver scroll 50 and driver scroll axis 96. Further, one or more mounting bolts (not shown in this view) may be disposed in the driver scroll flange structure 230. In addition, dowels or other technique could be used to ensure alignment between the driver scroll flange structure 230 and a driver scroll shaft 20, as well as ensure adequate rotational torque strength.

[0048] FIG. 3 illustrates an example of an isometric view of a cross-section of a lower portion of a scroll compressor according to some implementations. For example, Fig. 3 shows a driver scroll plate 52 and a seal plate 60. As mentioned, one or more passages (e.g., passages 220, 222, 224) for compressed suction gas passages may be disposed in the driver scroll plate 52 and these passages may be a hole or other cavity drilled or otherwise created in the driver scroll plate 52. The passages may open to each other or otherwise intersect to create a flow of gas under pressure through the driver scroll plate 52. The first axial passage 220 may open between an inner seal 252 and an outer seal 254 and corresponding grooves or channels 253, 255 in a bottom surface of the seal plate 60.

[0049] For example, the passages in the driver scroll plate 52 may include a first radial passage 222, a first axial passage 220, and a second axial passage 224. The first radial passage 222 may have a diameter greater than the respective diameter of the axial passages 220, 224 in the driver scroll plate 52. Also, the outer radial extent of the first radial passage 222 may be plugged with a plug. A first axial passage 220 may intersect with the first radial passage 222 at one opening and another opening may be disposed and open between the inner seal 252 and outer seal 254.

[0050] Further, a second axial passage 224 that intersects with the first radial passage 222 may be disposed inward of the first axial passage 220 in the radial direction. That is, one opening of the second axial passage 224 may open and intersect with the first radial passage 222 and the other opening of the second axial passage 224 may open into the driver scroll involute floor 53 between the walls of the spiral involute 54 of the driver scroll 50. During operation, for example, this opening allows compressed suction gas source to be supplied and the position of this opening is precise within the involute geometry to obtain the required pressure. During operation, the corresponding involute of the idler scroll 50 passes back and forth over this hole or opening, opening to different pressures in each pocket. For this reason, the diameter of this hole is small compared to the other opening of first axial passage 220. In some implementations, the first radial passage 222 may be 3 mm, the second axial passage 224 may be 0.7 mm, and the first axial passage 220 into seal chamber may be 2 mm. The hole or opening of the first axial passage 220 that is between the inner seal 252 and outer seal 254 is may be less than the opening to the compression pocket of the second axial passage 224, to minimize the transient back flow.

[0051] For example, the source of compressed suction gas enters second axial passage 224. This gas cycles from low to high pressure, as the compression involute pockets actually orbit. The second axial passage 224 starts out at the lowest pressure in a pocket, then increases to the highest pressure, before the adjacent wall of the spiral involute 54 of the driver scroll 50 passes over the second axial passage 224. Then a new low pressure enters the second axial passage 224. The diameter of first axial passage 220 is essentially very small, and this greatly limits the sinusoidal pressure variation inside the compressed suction gas chamber. It essentially averages the high and low pressure variation.

[0052] Fig. 3 further shows a driver scroll flange structure 230 that may essentially be cylindrical and may surround a portion of the main shaft 20. A lower portion of the driver scroll flange structure 230 may be disposed below a top surface 51 of the driver scroll plate 52, such as in a depression portion or recessed portion 351. Further, an annular seal 231 may be disposed between the lower portion of the driver scroll flange structure 230 and driver scroll plate 52 due to the difference of pressure (e.g., suction pressure).

[0053] As discussed above, Fig. 3 further shows by-pass valve cavity 232, the driver scroll flange structure 230, one or more reed valves 234 having a bolt or fastener 235 and a valve backer 236 may be disposed within the by-pass valve cavity 232 with the reed portions covering a by-pass port 238 when closed.

[0054] In some implementations, the driver scroll plate 52 includes two Oldham key support extensions 302 spaced equally apart around the driver scroll plate 52 and extending downward from the driver scroll involute floor 53 of the driver scroll plate 52. The Oldham key support extensions 302 enable the Oldham coupling 70 to fit between the scrolls, and directly engage each scroll plate 52, 82 to rotate in essentially perfect alignment. The Oldham key support extensions 302 may not extend downward from the driver scroll involute floor 53 of the driver scroll plate 52 as much as the spiral involute 54 extends downward. Further, the outer face of the Oldham key support extension 302 may be even with an outer surface of the driver scroll plate 52. Disposed within each key support extension 302 is a slot 310 for engaging with a driver scroll key (described below) of the Oldham coupling 70 having a corresponding shape to the slot 310. Additionally, there is adequate clearance between the inner face of the key support extension 302 and the outer wall of the spiral involute 54. The outer diameter of the driver scroll flange structure 230 may be smaller than the inner diameter of the seal plate 60 (so that there is a clearance).

[0055] In some implementations, the thrust plate 66 may be essentially disk shaped having a bore of an inner diameter that is concentric with respect to the driver scroll shaft 20 and an axial portion of the main frame 26. The top surface 61 and bottom surface 63 of the seal plate 60 may be flat and parallel. Further, one or more holes 310 may be disposed through the seal plate to accommodate a bolt 62, as shown. The holes 312 (and bolts 62) may be equally spaced apart.

[0056] In some implementations, each bolt 62 penetrates through the thrust plate 66 such that an end of each bolt is below the bottom surface. Further the bolts 62 may have a precision slip fit through the holes 312 of seal plate 60. In some examples, the bolts 62 may be threaded into the thrust plate 66. Additionally, in some examples, the bolts 62 may be threaded into the seal plate 60 and a head 64 of the bolt 62 may protrude below the thrust plate 66. Additionally, in some implementations, the seal plate 60 and the thrust plate 66 are parallel to one another and the thrust plate 66 maintains parallelism with the lower surface or bottom surface 83 of the idler scroll plate 82, in order to support the oil film pressure.

[0057] When the bolts 62 are tightened, there may be a specific length from each bolt head 64 to the top surface 67 of the thrust plate 66. One aspect of the parallelism between the seal plate 60 and the thrust plate 66 is to avoid idler scroll 80 thrust lubrication issues due to deflection. In some examples, the idler scroll 80 must maintain face to face contact with the driver scroll 50 while compressing gas; therefore the pull force of the seal plate 60 may transmit into an upward force from the thrust plate 66, which is parallel to the scroll set tip-to-floor contact axis. For example, when any type of axially compliant scroll compressor is in operation, an external gas pressure force is applied to one of the scrolls, and the other is fixed from moving in some way. During operation, for example, the idler scroll 80 is pushed into the driver scroll 50, by the thrust plate 66. A design objective is for the planes of respective involute tips (i.e., tip 55 of spiral involute 54 and tip 85 of spiral involute 84) and involute floors (i.e., driver scroll involute floor 53 and idler scroll involute floor 81) to make complete contact. A tip 55 may be a top surface of the spiral involute 54 and a tip 85 may be a top surface of the spiral involute 84. This thrust force of tip and floor is significant and must be adequate at all operating conditions; but not enough to damage the driver scroll involute floor 53 and idler scroll involute floor 81 surfaces. The idler scroll involute floor 81 may be the top surface of the idler scroll plate 82.

[0058] In some examples, two or more arc structures 86 may be disposed on the idler scroll 80 around respective arc portions of the essentially circular idler scroll plate 82. The arc structures 86 may be aligned with another along a diameter of the idler scroll plate 82 and may each be symmetrical. Further the arc structures 86 may extend upward from the idler scroll involute floor 81 of the idler scroll plate 82 toward the driver scroll plate 52. A top surface 88 of the arc structure 86 may be even with a tip 85 of the spiral involute 84 of the idler scroll 80. Details of the arc structures 86 will be described below.

[0059] Fig. 3 further shows examples of the thrust plate 66, idler scroll hub 256, idler scroll bearing 94, slider block 264, which is over the idler shaft hub 260. Additionally, the oil supply tube 92 is shown, which may connect to an oil passage 272 within the idler shaft hub 260. [0060] Fig. 4 illustrates an example of a top view of a cross-section of a lower portion of a compressor according to some implementations. Fig. 4 shows a top view of a cross-section taken along line A-A of Fig. 2 and is shown at a crank angle of 140°, for example. Fig. 4 shows, for example, a vertical center driver scroll axis 96 and a vertical center axis of the idler scroll axis 98, which is offset from the driver scroll axis 96 as mentioned above. This offset is mathematically equal to the orbit radius of the involute design. Fig. 4 further shows the spiral involute 54 of the driver scroll and the spiral involute 84 of the idler scroll 80. An Oldham coupling 70 is also shown.

[0061] In some implementations, the arc structures 86 may be disposed in an arc shape around respective arc portions of the essentially circular idler scroll plate 82. For example, one arc structure 86 may be disposed across the idler scroll plate 82 from another arc structure 86 along a diameter. Further, each arc structure 86 may be symmetrical with respect to a diameter bisecting each arc structure 86. The arc structures 86 each may have a planar or flat top surface 88 which may be even with each other and may be even with a tip 85 of the spiral involute 84. As mentioned above, the tip 85 may contact the driver scroll involute floor 53 of the driver scroll plate 52 during operation of the compressor 1. Accordingly, the top surface 88 of each arc structure 86 may provide stability during operation since the top surface 88 may contact the driver scroll involute floor 53 to prevent tilting or tipping, for example, during operation. Further, the two arc structures 86 and respective top surfaces 88 (stabilizing surfaces) may be disposed in alignment with the peak of the Ftg force vectors such that the respective Ftg force vectors bisect the arc structures 86. This will later be explained in detail. Additionally, the Ftg force vectors may be perpendicular to the driver scroll axis 96 and the idler scroll axis 98.

[0062] Fig. 5 illustrates an example of a top view of an idler scroll according to some implementations. Fig. 6 illustrates an example of a perspective view of an idler scroll according to some implementations. In some implementations, one or more concave portions 520, which may be cut-outs, may be disposed in the outer edge or diameter 602 of the idler scroll plate 82. The concave portions 520 may be spaces for the bolts 62 to extend past the outer diameter or edge 602 of the idler scroll plate 82 to the thrust plate 66. Accordingly, during operation of gas compression, the idler scroll plate 82 may not contact the bolts 62. The one or more concave portions 520 are shown as curved surfaces, but the concave portions may be shaped in different ways with straight lines and edges.

[0063] Additionally, according to some implementations, one or more idler scroll Oldham key slots 506 may be disposed in the outer edge or diameter 602 of the idler scroll plate 82. The Oldham key slots 506 may essentially be grooves, cut-outs or indentations and may essentially be U-shaped or have another shape corresponding to the idler scroll key portions of the Oldham coupling 70. Further, the Oldham key slots 506 have bottom floor sections 508 or structures such that the key slots 506 do not penetrate the entire way through the idler scroll plate 82 and the bottom surface 83 of the idler scroll plate 82 is uninterrupted to ensure lubrication against the thrust plate 66. The bottom floor section 508 may be a recessed portion in the idler scroll involute floor 81. As shown in Fig. 6, one or more balance holes 620, which may be bores 620, extend inwardly in the radial direction may be drilled or otherwise created in the idler scroll plate 82.

[0064] As shown in Fig. 6, for example, arc structures 86 may extend or protrude from a portion of the idler scroll involute floor 81 of the idler scroll plate 82 and may face each other across the idler scroll plate 82 with the spiral involute 84 between them. There may be two arc structures 86, as shown, but more than two arc structures 86 may be included on the involute floor 81 of the idler scroll plate 82. That is, the arc structures 86 may be disposed along respective arc sections of the circumference of the essentially circular idler scroll plate 82 and the outer surfaces 530, such as outside edges or faces, of the arc structures 86 may have equal arc lengths. The arc structures 86 may be aligned with another along a diameter of the idler scroll plate 82 and may each be symmetrical with respect to the diameter bisecting each arc structure 86. The two or more arc structures 86 may also have the same mass and may be made of the same material of the spiral involute 84 of the idler scroll 80. [0065] Further, each outer surface 530, may be contiguous with an outer surface 602 of the idler scroll plate 82. That is, for example, an outer surface 530 of each arc structure 86 may be shaped as an arc and may extend upwards along respective arc portions of the idler scroll plate 82. A radial thickness of each arc structure 86 may be the same and may depend on a desired mass due to balancing. The radial thickness of each arc structure 86 may be defined by side portions 532, 534 that extend radially inward toward a center of the idler scroll 80 from the outer surface 602. These side portions 532, 534 may be curved and have rounded edges. Further, an inner surface 536 of each arc structure 86 may have an arc shape corresponding to the arc shape of the outer surface 530. The inner surface 536 and outer surface 530 may be smooth and have a curvature corresponding to respective arc portions of the outer circumference of the idler scroll plate 82.

[0066] A top surface 88 of each arc structure 86 may be flat and smooth and may be in a same plane as the tip 85 of the spiral involute 84. Accordingly, each arc structure 86 may extend upward toward the driver scroll plate 52 and a top surface 88 may be machined to be in the same horizontal plane as the tip 85 of the spiral involute 84 of the idler scroll 80. The horizontal plane may be perpendicular to the driver scroll axis 96. That is, during operation the contact of the top surface 85 of the arc structures 86 with the driver scroll involute floor 53 of the driver scroll 52 may provide stability by preventing tipping or rocking of the idler scroll 80.

[0067] With respect to certain forces during operation, while the radial gas force Frg contributes to a combined resultant force, its effect is very small on the overturning moment (tipping), as well as the shaft bearing loads. Therefore, Ftg is a focal point of consideration herein. The Ftg vector may be among the most challenging force with respect to stability, since the overturning moment produces instability of the compression sealing surfaces, which are the respective involute tips 55, 85 and involute floors 53, 81 of both scroll members (i.e., driver scroll 50 and idler scroll 80). In a Co-Rotating scroll, the Ftg vector remains essentially fixed in radial location, with respect to the housing. Therefore, the arc structures 86 are aligned with the Ftg force vector, as mentioned above and shown in at least Fig. 4. That is, as shown in Fig. 5, for example, one arc structure 86 may be aligned to be symmetrical with respect to the Ftg force vector of the idler scroll 80 and another arc structure 86 may be aligned and symmetrical with respect to the Ftg force vector of the driver scroll 50. Accordingly, the two arc structures 86 may be disposed essentially 180° apart from each other around a circumference of the essentially circular idler scroll plate 82. Further, as shown in Fig. 3, for example, the two arc structures 86 provide extended moment arms to reduce the overturning moment, due to the peak magnitude of the Ftg gas force.

[0068] Fig. 7 illustrates an example of a free-body diagram showing certain forces and moments for components of a comparative example of a compressor according to some implementations. Fig. 7 includes significant certain force vectors, applicable moment arms and distances, which may be important to the goal of stability at all envelope conditions. The following Table 1 indicates definitions of the forces, moments, and distances included in Fig. 7.

Table 1: [0069] In Table 1, Pdisch means discharge pressure of the gas, “area of driver shaft” means the area of the diameter of the driver scroll shaft 20 and “area of idler shaft” means area of the diameter of the idler shaft hub 260. It is understood by those skilled in the art, that the axial Fag, tangential Ftg, and radial Frg gas forces combine to force the scroll set apart, and resist the compression process. In some instances, the tangential gas force Ftg may be greater than the radial gas force Frg. Therefore external gas forces described earlier, may be strategically applied to maintain compression stability. It is understood that if the restoring forces are excessive, then additional power is consumed, which reduces compressor performance; along with reliability concerns. For example, the restoring forces may be Fmass, Fdp+Fip, Fdp2, and Ftp. The Ftg gas force may be the most challenging force, since it primarily produces the overturning moment during compression, as mentioned above. For example, Fig. 4 shows the Ftg forces as acting on both the driver scroll 50 and idler scroll 80 in opposite directions.

[0070] Fig. 7 identifies, for example, a force Fob associated with the outboard bearing 22 of the driver scroll shaft 20 and a force Fmb associated with a main bearing 24 of the driver scroll shaft 20. Since there is a much larger distance Z6 between Fob and Fmb, the secondary overturning moment of the Ftg vector times the moment arm of Z4 has less overturning effect than the idler scroll 80. For those skilled in the art, it is also known that the primary overturning moment of instability in a scroll compressor is the Ftg vector times the moment arm of Zl. The primary overturning moment is then with the idler scroll 80 and is clockwise in this diagram. However, in a co-Rotating design there is a secondary overturning moment with the driver scroll 50; but this is better contained by the larger moment arm Z6. Through the equations defined below, as well as the free-body diagram of Fig. 7, significant metrics which define optimum stability are the tip thrust force Ftt and the available radius Rtt, which is explained in more detail below. Further, for a given compressor operating condition, the generated gas forces will vary significantly within a single orbit, or crank angle of 360 degrees. The overturning moment of Ftg times Zl will require that Ftt must remain a positive number, across the entire perimeter of each involute tip 55, 85, throughout the compression orbit. A failure to achieve this, at all operating conditions, will release compressed gas back into the suction gas; and significantly reduces performance. Finally, maximizing the moment arm of Rtt can be effective, and also minimizes excess applied thrust force; which will generate additional power and reliability risk. Rtt may be a function of the involute geometry, including wrap pitch and end angle. Therefore, the value of Rtt changes throughout an orbit cycle. [0071] For example, EQ1 defines that the thrust plate 66 force Ftp against the idler scroll 80 is equal to the intermediate pressure force against the seal plate Fip.

[0072] EQ1 Ftp = Fip

[0073] EQ2 describes a sum M (driver scroll 50) about the main bearing 24.

[0074] EQ2 Ftt * Rtt + Ftg * Z4 = Fdtb * Rdtb + Fob * Z6

[0075] EQ3 describes a sum Fz of the driver scroll 50.

[0076] EQ3 Ftt = Fdp + Fip + Fdtb - Fag + Fmass

[0077] EQ4 describes a sum M (idler scroll 80) about the idler scroll bearing 94.

[0078] EQ4 Ftp * Rtp = [Ftg * Z1 - Ftt * Rtt]

[0079] EQ5 describes a sum Fz of the idler scroll 80.

[0080] EQ5 Ftp = Ftt +Fag - Fdp2

[0081] A summary of the equations above (EQ1 through EQ5) may be described as: [0082] EQ6 Fdtb = Ftt +Fag - Fdp - Fip

[0083] EQ7 Ftt = Fip - Fag + Fdp2

[0084] Additionally, Moments from driver scroll 50 may be described in EQ8 and Moments from idler scroll 80 may be described in EQ9.

[0085] EQ8 Rtt = (Fdtb * Rdtb + Fob * Z6 - Ftg * Z4) / Ftt

[0086] EQ9 Rtp = (Ftg * Z1 - Ftt * Rtt) / Ftp

[0087] Fig. 8 illustrates an additional free-body diagram showing forces and moments for components of an example of a compressor according to some implementations. Fig. 8 includes certain force vectors, applicable moment arms and distances, which may be important to the goal of stability at all envelope conditions. Notably the free-body diagram of Fig. 8 shows two or more arc structures 86 extending upward from the idler scroll involute floor 81 of the idler scroll plate 82. Each of the two or more arc structures 86 may include an essentially flat or planar top surface 88, which may be referred to as a stabilizing surface.

[0088] As shown in Fig. 8, and as mentioned above, the two top surfaces 88 of the arc structures 86 are centrally aligned along the Ftg vector (as shown in Fig. 5, for example). For example, centrally aligned may mean that a line that passes through the center of each arc structure 86, also passes symmetrically between the driver scroll axis 96 and the idler scroll axis 98, as shown in Fig 4, for example. As mentioned earlier in the document, in a co-rotating scroll mechanism these vectors remain essentially in a fixed position with respect to the compressor frame. However, as the scroll set rotates, the magnitude of the Ftg vector is cyclic from a maximum to a minimum. As shown in Figs. 4 and 5, the maximum Ftg occurs where each arc structure 86 is aligned. Therefore, both Figs. 7 and 8 are shown at the position of maximum Ftg. Also, as the scrolls rotate the arc structures 86 rotate. However, as stated, the Ftg vector remains in the same direction.

[0089] Fig. 9 illustrates an example of a top view of a cross-section of a lower portion of a compressor according to some implementations. Fig. 9 shows, for example, the driver scroll axis 96 and the idler scroll axis 98, which is offset from the driver scroll axis 96 as mentioned above. Fig. 9 further shows the spiral involute 54 of the driver scroll 50 and the spiral involute 84 of the idler scroll 80. An Oldham coupling 70 is also shown.

[0090] Fig. 9 further shows two arc structures 86, which may be disposed in an arc shape around respective arc portions of the idler scroll plate 82. Fig. 9 also shows a profile 902 of an available radius Rtt, which may be a defined magnitude throughout the 360° compression crank angle. As identified in Fig. 9, the available radius profile is a maximum value at each arc structure 86 and top surface 88. As the scroll set proceeds through the entire 360 degrees, the available radius profile 902 reduces because it is provided only by the outer form of the spiral involute 54 of the driver scroll 50 and spiral involute 84 of the idler scroll 80. These of course extend and contract during the compression cycle. Accordingly, in some implementations, as the driver scroll 50 and the idler scroll 80 rotate, the available radius profile 902 also rotates. As shown in Figure 5, the Ftg vector remains in the same direction with respect to the compressor housing, but its magnitude changes significantly as the rotation occurs. Plots of this force, as well as other important metrics, are described in more detail below.

[0091] Fig. 10 illustrates an example of a cross-sectional view of a lower portion of a scroll compressor according to some implementations. Fig. 10 represents a same view as Fig. 2 may include the same or similar structural elements. Therefore, some elements shown in Fig. 10 that are also shown and described in Fig. 2 may not be repeated here.

[0092] As mentioned above, in some implementations, a lubricant, such as oil, may be supplied to the lower portion of the compressor 1 by an oil supply tube 92 that may be sealed with a seal 210 into the main frame 26. Accordingly, an oil supply tube 92 may supply oil pressurized by discharge gas to an oil supply tube inlet 270 and may be sealed at the oil supply tube inlet 270 by a seal 271. Drilled and otherwise created in the idler shaft hub 260 may be an oil passage 272, which may include a radially extending oil passage 282 and an axially extending oil passage 284 that intersect each other in the base portion 290 of the idler shaft hub 260. As shown, one end of the radially extending oil passage 282 connects with the oil supply tube 92. The axially extending oil passage 284 extends upward through a top surface 286 of the idler shaft hub 260 and may open to a clearance or gap 292 between the idler shaft hub 260 and the slider block 264.

[0093] As mentioned above, in some examples, an axially extending oil metering passage 274 may be drilled or otherwise created through a top portion of the slider block 264. A lower end of the oil metering passage 274 may be open to and intersect with the clearance or gap 292. A top end of the oil metering passage 274 may be open to and intersect with a clearance or gap 1305 between the top surface 1304 of the slider block 264 and a portion 1303 of the bottom surface 83 of the idler scroll plate 82. The oil metering passage 274 may be a passage for oil to pass through.

[0094] Further, in some implementations a rounded protrusion 1334 is disposed or extends from the top surface 1304 of the slider block 264. Also, in some examples, the rounded protrusion 1334 is aligned with the axis of the idler shaft hub 260. The rounded protrusion 1334 may contact the portion 1303 of bottom surface 83.

[0095] In some implementations, there may be oil passages or grooves disposed within each arc structure 86. While the diameter of the driver scroll shaft 20 is most important to the strength and deflection requirements, it then determines the axial compliant Pd force, as well as. Of course the idler shaft hub 260 diameter also has a similar Pd force upward. As an example, a balance of discharge pressure Pd and intermediate pressure Pi is approximately 40% discharge and 60% intermediate. This balance may produce an acceptable thrust force between the scroll set, for essentially all conditions within the operating envelope. For example, if the discharge component were too large, then the thrust force at high load and high ratio conditions would be excessive. This force component for axial compliance could in fact be excessive for such a condition, and cause failure. However, reducing the driver scroll shaft 20 diameter and therefore the discharge pressure force component, might yield a shaft design that could not withstand the forces and moments, or support the hydrodynamic oil film of a journal bearing. Accordingly, an objective of including the oil grooves or passages in the arc structures 86 may be to reduce the thrust force between the two scrolls, produced by the discharge pressure component only. Additionally, the Pd oil pressure in each small area, is separated from Ps suction gas, by very small perimeter walls. Therefore as the relative orbiting motion between top surface 88 and the driver scroll involute floor 53 occurs, a small amount of this oil will leak past the arc structure 86 and lubricate the highly loaded thrust surfaces. In addition, this amount of oil passing into Ps suction pressure will slightly reduce the Pd oil pressure in each chamber. However, the arc structure 86 areas produce essentially Pd forces which can effectively reduce the overall tip thrust load, with minimal effect to the Pi intermediate forces.

[0096] For example, an oil passage or path, which may consist of an axial plate passage 1352, a radial passage 1354, and an axial arc passage 1356 may be included in each arc structure 86 for allowing oil to pass. A shape of each oil passage 1352, 1354, 1356 may be circular, oblong, or oval in cross-section. That is, in the implementation shown in Fig. 10, two arc structures 86 are shown opposite the idler scroll plate 82 to one another and therefore two oil passages or paths are shown.

[0097] In some implementations, an axial plate passage 1352, which may be disposed parallel to the driver scroll axis 96 with a lower end open to and in communication with a clearance or gap 1305 between a top surface 1304 of the slider block 264 and a portion 1303 of the bottom surface 83 of the idler scroll plate 82. A top end of the axial plate passage 1352 may be open to and in communication with a radial passage 1354.

[0098] Each radial passage 1354 may extend through a portion of the idler scroll plate 82 in the radial direction and have a portion open to and in communication with the axial plate passage 1352 and axial arc passage 1356. The outer end of the radial passage 1354 may be plugged or capped with a plug 1368, for example.

[0099] Each axial arc passage 1356 may be disposed along an axial direction within each arc structure 86 and may have a curved or arc shape that conforms with the curved or arc shape of the arc structure 86. Further, in some implementations the axial arc passage 1356 may be circular in cross-section through the arc structure 86. Further the axial arc passage 1356 may open to a top surface opening 1402 that may be arc or curved shaped. The top surface opening 1402 may be arced or curved shaped and may be symmetrical with respect to the axial arc passage 1356, which may be disposed in the center of the arc structure 86. The axial arc passage 1356 may also be aligned with a center of the respective arc structure 86.

[00100] Fig. 11 illustrates an example of a top view of a cross-section of a lower portion of a compressor according to some implementations. Fig. 11 shows a top view of a cross-section taken along line B-B of Fig. 10. For reference, Fig. 11 shows, for example, the driver scroll axis 96 and the idler scroll axis 98, which is offset from the driver scroll axis 96 as mentioned above. Fig. 11 further shows the spiral involute 54 of the driver scroll 50 and the spiral involute 84 of the idler scroll 80. An Oldham coupling 70 is also shown.

[00101] Fig. 11 further shows the top surface opening 1402 that is in communication with the respective axial arc passages 1356. Further, as discussed above, the opening 1402 may have an arc shape corresponding to the arc shape of the arc structure 86. In some examples, the opening 1402 may be circular or oblong.

[00102] Accordingly, in some implementations, oil may pass through the oil supply tube 92 and into a radially extending oil passage 282 of the idler shaft hub 260. The oil may pass through the axially extending oil passage 284 within the idler shaft hub 260 into a clearance or gap 292 between the idler shaft hub 260 and the slider block 264. Some oil may then continue through the oil metering passage 274 and into a clearance or gap 1305 between a top surface 1304 of the slider block 264 and a portion 1303 of the bottom surface 83 of the idler scroll plate 82. Oil may also pass through an axial plate passage 1352, radial passage 1354 and an axial arc passage 1356 of an arc structure 86 through the opening 1402 in a top surface 88 thereof. [00103] Fig. 12 illustrates an example of a free-body diagram showing certain forces and moments for components of an example of a compressor according to some implementations. Fig. 12 includes certain force vectors, applicable moment arms and distances, which may be an important to the goal of stability at all envelope conditions. The free-body diagram of Fig. 12 shows two or more arc structures 86 extending upward from the idler scroll involute floor 81 of the idler scroll plate 82 of the idler scroll 80.

[00104] Fig. 12 shows the Fdp_oil pressure force, as well as the Rdp_oil moment arm. EQ10 takes into account the Fdp_oil force and EQ11 takes into account the Rdp_oil moment arm.

[00105] EQ10 Ftt = Fip - Fag + Fdp2 - Fdp_oil

[00106] EQ11 Rtp = (Ftg * Z1 - Ftt *Rtt - Fdp_oil *Rdp_oil) / Ftp

[00107] Accordingly, the component of Pd discharge pressure axial force may be reduced. [00108] As mentioned above, the tangential gas force Ftg does not rotate with the 360° compression crank angle. It changes magnitude, but is in a fixed location with respect to the housing. Since the Ftg force has a high peak value, stabilizing arc structure 86 supports are located on one of the two scrolls, and the surfaces 88 are in the same plan as the involute tip 85 and floor planes 52.

[00109] Basic stability may be controlled with the involute outer perimeter of the idler scroll 50 and the driver scroll 50, though the magnitude of the Ftg force and stability are changing. This may be referred to as available radius. In some implementations, the arc structures 86 act as extended radius support and may be located only at the peak overturning stability area, during the relative orbiting motion. [00110] FIG. 13 illustrates an example of a cross-sectional view of a lower portion of a scroll compressor according to some implementations. FIG. 14 illustrates an example of an isometric view of a cross-section of a lower portion of a scroll compressor according to some implementations. In general, Figs. 13 and 14 show arc structures 1386 extending from an involute floor of the driver scroll plate 52, instead of arc structures 86 extending from the idler scroll involute floor 81 of the idler scroll plate 82. In the implementations shown in Figs. 13 and 14, arc structures 86 extending from the idler scroll plate 82 are not included. Other components shown in Figs. 13 and 14 are the same or similar to the elements shown in Figs. 2 and 3, respectively, and are therefore not described here.

[00111] In some implementations, the arc structures 1386 may be disposed in an arc shape around respective arc portions of the essentially circular driver scroll plate 52. For example, one arc structure 1386 may be disposed across the driver scroll plate 52 from another arc structure 1386 along a diameter. Further, each arc structure 1386 may be symmetrical with respect to a diameter bisecting each arc structure 1386. The arc structures 1386 each may have a planar or flat top surface 1388 which may be even with each other and may be even with an involute tip 55 of the spiral involute 55. The involute tip 55 may contact the idler scroll involute floor 81 of the idler scroll plate 82 during operation of the compressor 1. Accordingly, the top surface 1388 of each arc structure 1386 may provide stability during operation since the top surface 1388 may contact the idler scroll involute floor 81 to prevent tilting or tipping, for example, during operation. Further, the two arc structures 1386 and respective top surfaces 1388 (stabilizing surfaces) may be disposed in alignment with the peak of the tangential force vectors such that the respective Ftg force vectors bisect the arc structures 1386.

[00112] The processes described herein are only examples for discussion purposes. Numerous other variations will be apparent to those of skill in the art in light of the disclosure herein. Further, while the disclosure herein sets forth several examples of suitable frameworks, architectures and environments for executing the processes, the implementations herein are not limited to the particular examples shown and discussed. Furthermore, this disclosure provides various example implementations, as described and as illustrated in the drawings. However, this disclosure is not limited to the implementations described and illustrated herein, but can extend to other implementations, as would be known or as would become known to those skilled in the art.

[00113] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claims.