TECHNICAL FIELD

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

BACKGROUND

[0002] Scroll compressors are widely used in refrigerant compression applications including variable refrigerant flow (VRF) systems. Scroll compressors may include a scroll pair including a fixed scroll and an orbiting scroll having an intermeshing pair of spiral involutes, that form crescent shaped pockets of refrigerant gas during operation. For example, suction gas enters the compressor and then enters the outside perimeter of the scroll pair. The compression pockets reduce in volume as the orbiting motion occurs, and this compresses the gas to a higher pressure. Near the center section, the compression pockets reach the discharge port in the fixed scroll and the high pressure (compressed) gas exits out of the top. In a VRF high-side scroll, the high pressure discharge gas may then generally flow downward, between the pump cartridge and the housings, and then exit the compressor.

SUMMARY

[0003] Some implementations include arrangements and techniques for a compressor, which may include an orbiting scroll having a spiral involute extending in an axial direction from an orbiting scroll plate; a fixed scroll having a spiral involute, extending in the axial direction from a fixed scroll plate, that is intermeshed with the spiral involute of the orbiting scroll; a drive shaft driving the orbiting scroll having an eccentric portion which on which an orbiting scroll bearing supporting the orbiting scroll is disposed; a fixed main frame supporting a main bearing of the drive shaft; an axial cylinder that is moveable in the axial direction that is disposed concentrically with respect to the drive shaft. In some implementations, the axial piston includes a top surface that is parallel with a bottom surface of the orbiting scroll plate, and a bottom rim extending inward toward the drive shaft in a radial direction.

BRIEF DESCRIPTION OF THE DRAWINGS [0004] 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. [0005] FIG. 1 illustrates an example of a cross-sectional view of a scroll compressor according to some implementations.

[0006] FIG. 2 illustrates an example of a detailed cross-sectional view of an upper portion of a scroll compressor according to some implementations.

[0007] FIG. 3 illustrates an example of an isometric view of an axial piston of a scroll compressor according to some implementations.

[0008] FIG. 4 illustrates an example of a top view of an axial piston of a scroll compressor according to some implementations.

[0009] FIG. 5 illustrates an example of a cross-sectional view of an upper portion of a scroll compressor according to some implementations.

[0010] FIG. 6 illustrates an example of a free-body diagram showing certain forces and components of a scroll compressor according to some implementations.

[0011] FIG. 7 illustrates an example of a detailed cross-sectional view of an upper portion a compressor according to some implementations.

[0012] FIG. 8 illustrates an example of a perspective view of a counterweight of a compressor according to some implementations.

[0013] FIG. 9 illustrates an example of a perspective view of a counterweight of a compressor according to some implementations.

[0014] FIG. 10 illustrates an example of a perspective view of a counterweight guide plate of a scroll compressor according to some implementations.

[0015] FIG. 11 illustrates an example of a top view of a piston thrust plate of a compressor according to some implementations.

[0016] FIG. 12 illustrates an example of a top view of a portion of an axial piston of a compressor according to some implementations.

[0017] FIG. 13 illustrates an example of a slider block of a compressor according to some implementations .

[0018] FIG. 14 illustrates an example of an isometric view in cross-section of portions of a scroll compressor according to some implementations.

[0019] FIG. 15 illustrates an example of a detailed cross-sectional view of an upper portion a compressor according to some implementations.

[0020] FIG. 16 illustrates an example of a top view of an axial piston of a compressor according to some examples. [0021] FIG. 17 illustrates an example of a cross-sectional view of an upper portion of a scroll compressor according to some implementations.

DESCRIPTION OF THE EMBODIMENTS

[0022] The respective involutes of the orbiting scroll and fixed 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 fixed scroll and the high pressure gas exits through this port. In some implementations the scroll compressor described herein may be described as a “high side” design, which may mean that there is direct suction into the compression chamber and most of the interior of the housing is at a discharge pressure. Additionally, the implementations and examples of the scroll compressor described herein may be a hermetic design, meaning that it is completely sealed from ambient surroundings. The scroll compressor described herein may also be applied to a low side design or a semi-hermetic scroll design.

[0023] The spiral involute of the orbiting scroll and the spiral involute of the fixed scroll intermesh and the orbiting scroll orbits with respect to the fixed scroll. The fixed scroll may be fixed or held rigidly within a press fit and/or pinch fit assembly, and is aligned with the center axis of the compressor. During operation, as the orbiting scroll and the fixed scroll compress gas, internal forces act to separate the orbiting scroll and fixed scroll in at least the axial direction and the radial direction. This may cause instability and may further cause a reduction in efficiency. Axial compliance is a mechanism applied to a scroll set to maintain stability during compression. In some examples, the tip or top surface of the spiral involute of the orbiting scroll makes continuous or constant contact with the spiral involute floor of the fixed scroll and the tip or top surface of the spiral involute of the fixed scroll makes continuous or constant contact with the spiral involute floor of the orbiting scroll.

[0024] Additionally, gas pressures applied to areas under the orbiting scroll may act to force the orbiting scroll and fixed scroll together during compression in the axial direction. In this type of axial compliance an intermediate gas pressure may be applied to an area and a discharge gas pressure may be applied to a different area and each contributes to a portion of the stability force. The intermediate pressure may be compressed suction gas and this along with the discharge pressure force can maintain stability throughout the operating envelope. In some implementations discussed herein an axial piston may contribute to an axial force to maintain the orbiting scroll in uniform contact with the fixed scroll. The axial piston contributes to ensuring stability of the orbiting scroll, but also minimizes the high axial thrust forces, which consume significant power during compression.

[0025] FIG. 1 illustrates an example of a cross-sectional view of a scroll compressor 1 according to some implementations. The body or housing of the compressor 1 may include an upper cap 2, center shell 4, and a lower cap 6. These components may be press fit together, as shown in upper press fit portion 12 and lower press fit portion 14. The lower cap 6 or base may essentially be bowl-shaped having a curved bottom with a vertically extending rim that is essentially centered on the drive shaft axis 96, which is a main axis or central axis of the scroll compressor 1. The lower cap 6 may also have a vertically extending outer rim concentric with the drive shaft axis 96 for engaging with a portion of the center shell 4 at lower press fit portion 14. The lower cap 6 may have an open end or face into which components such as an oil tube 92 may protrude into. The center shell 4 may essentially be cylindrical having an axis parallel to the drive shaft axis 96 and may be concentric to the bore(s) of the one or more bearings on the drive shaft (main 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 metal or steel tubing or the like. Further, the fixed scroll 80 may be affixed to or press fit into the center shell 4 and may be centered with respect to the drive shaft axis 96. 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. [0026] A discharge outlet 8 may be disposed in the center shell 4 which is an outlet for discharge pressure gas. Further, the upper cap 2 may essentially be a bowl-shaped having a curved top with a vertically extending rim that is essentially centered on the drive shaft axis 96. The upper cap 6 may also have a vertically extending outer rim concentric with the drive shaft axis 96 for engaging with a portion of the center shell 4 at upper press fit portion 12. A suction inlet 10 connected to a suction passage 11 may be disposed in the upper cap 2 to suction a refrigerant gas or a liquid or a mixture of liquid and gas directly suctioned into a compression chamber formed by the intermeshed spiral involute 54 of the orbiting scroll 50 and spiral involute 84 of the fixed scroll 80. The suction pressure gas Ps may be contained around the entrances of the spiral involute 54 and the spiral involute 84 and may be drawn into compression from there.

[0027] The drive shaft 20, which may be a main drive shaft, is aligned or centered along the drive shaft axis 96 or main axis and may be supported by a main bearing 24 and/or a lower bearing 94 such that the drive shaft 20 may be rotated to very high speeds by a motor rotor 18, operating inside the motor stator 16. For instance, the main frame 26 and main bearing 24 are secured to the upper end of the center shell 4, such that drive shaft axis 96 through the main bearing 24 is centered within the center shell 4. A lower bearing frame 95 frame and lower bearing 94 are secured at the lower end of the center shell 4, such that the drive shaft axis 96 through the main bearing 24 and lower bearing 94 is also centered within the center shell 4. The main bearing 24 and lower bearing 94 are therefore secured in the center shell, such that each one is perpendicular to the ends of the center shell 94, and a single axis (drive shaft axis 96) then passes through the main bearing 24 and lower bearing 94. The orbiting scroll 50 centerline is then a separate axis, located mathematically at the orbit radius from the drive shaft axis 96.

[0028] In general, the drive shaft drives the orbiting scroll 50. The motor rotor 18 and motor stator 16, may be referred to herein as the motor components. Further, a main frame 26 may be press fit inside center shell 4. Since the main bearing 24 is concentric with the main frame 26 pressing diameter, the drive shaft 20 will then be aligned concentrically with the motor stator 16. Upon operation, the motor stator 16 imparts a magnetic field such that the motor 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 54 of the orbiting scroll 50 and the spiral involute 84 of the fixed scroll 80 upon operation. In some implementations, the motor components (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] The lower bearing 94 may be supported by a lower bearing frame 95, which may be press fit or inserted into the center shell 4. A lubricant, such as oil, from the lower portions of the assembly (e.g., lower cap 4) may be drawn up an oil passage 23 inside the drive shaft 20 during operation. The lubricant may collect in the lower cap 4 as indicated by lubricant line 91 and may be suctioned from an opening 93 in the oil tube 92. For example, the lubricant may be used to lubricate the lower bearing 94, main bearing 24, and orbiting scroll bearing 25. In addition, there are orbiting thrust surfaces which require lubrication. In some implementations an oil tube 92, which may be referred to as an oil pick-tube, with an opening 93 may extend in an axial direction toward the lower cap 4 from the drive shaft 20 and suction a lubricant as the drive shaft 20 rotates.

[0030] Fig. 1 further shows an eccentric portion 22 of the drive shaft 20 on the upper end of the drive shaft 20. The eccentric portion 22 may be a shaft eccentric, pin, or journal that may extend axially from the upper end of the drive shaft 20 that may be driven by the motor components to thereby impart orbital motion to the orbiting scroll 50. The axis of the eccentric portion 22 is offset from the drive shaft axis 96, which is aligned with the drive shaft 20. The eccentric distance may essentially be defined by the orbit radius of the pair of the spiral involute of the orbiting scroll 54 and the spiral involute of the fixed scroll 80. A slider block (not shown in this implementation) may also be disposed which, in some implementations may be a sintered, hardened, and ground component, which forms a journal for the orbiting scroll bearing 25. Additionally, a counterweight 60 may be disposed on the drive shaft 20 above the motor rotor 18 and essentially below the main frame 26. Further, in some implementations and as shown in Fig. 2, an Oldham coupling 70 may be disposed between the fixed scroll 80 and the orbiting scroll 50. The relative orbiting movement between the orbiting scroll 50 and the fixed scroll 80 may be realized by Oldham coupling 70. As mentioned above, the eccentric portion 22 rotates the orbiting scroll 50 in a specific circular path. The Oldham coupling 70 maintains strict X-Y alignment between the spiral involute 84 of the fixed scroll 80 and the spiral involute 54 of the orbiting scroll 50.

[0031] The spiral involute 54 of the orbiting scroll 50 extends upward toward the fixed scroll 80 from the orbiting scroll involute floor 51 of the orbiting scroll plate 52. The orbiting scroll plate 52 may essentially be circular in some examples. Additionally, the spiral involute 84 of the fixed scroll 80 extends downward toward the orbiting scroll 50 from the fixed scroll involute floor 81 of the fixed scroll plate 82. The fixed scroll plate 82 may essentially be circular in some examples. When revolving the orbiting scroll 50 by driving the motor components (e.g., motor rotor 18, motor stator 16), for example, a refrigerant gas passes through the suction inlet 10, and is guided into a compression chamber 34 formed by the spiral involute 54 of the orbiting scroll 50 and the spiral involute 84 of the fixed scroll 80. Then, the refrigerant gas in the compression chamber(s) 34 is reduced in volume to be compressed as it moves toward the center between the orbiting scroll 50 and the fixed scroll 80. The compressed refrigerant gas may be discharged from a discharge port 28 of the fixed scroll 80. The compressed refrigerant gas may also be discharged through small bypass valves, strategically located inside the fixed scroll involute floor 81, and connected directly to the discharge port 28. In some examples, the discharge port 28 is a passage that opens to the compression chamber(s) 34 in the fixed scroll involute floor 81, through fixed scroll plate 82 and open through the fixed scroll main body 83. In some examples, one or more bypass valves 30 may be disposed in the fixed scroll main body 83. A bypass passage 32 may be disposed through the fixed scroll main body 83 to an opening in the fixed scroll involute floor 81. Also, in some examples, a check valve 40 in communication with the suction passage 11 may be disposed through a portion of the fixed scroll 80. The check valve may have a valve head 42 attached to a spring 41. In some examples, the suction passage 11 and the check valve 40 are essentially cylindrical and may be essentially coaxial.

[0032] Additionally, in some implementations, an axial piston (axial cylinder) 100 may be disposed concentrically with respect to the drive shaft 20 and below the orbiting scroll plate 52 in the axial direction. The axial piston 100 will be described in more detail below and may be referred to as an axial cylinder.

[0033] FIG. 2 illustrates an example of a detailed cross-sectional view of an upper portion of a scroll compressor according to some implementations. In some implementations, the orbiting scroll hub 56 extends from a bottom surface (or lower surface) 53 of the orbiting scroll plate 52 and is essentially concentric with the eccentric portion 22 of the drive shaft 20. In some implementations, the orbiting scroll hub 56 is essentially cylindrical and has an open bottom and surrounds and engages with the orbiting scroll bearing 25, which is disposed around the eccentric portion 22. Further, an oil passage 23 extending through the drive shaft 20 and eccentric portion 22 extends to an opening 90 in a top surface 21 of the eccentric portion 22. The lubricant, such as oil, may pass through the oil passage 23, through the opening 90 and into a gap 57 between the bottom surface 58 (of the orbiting scroll plate 52 that is within the orbiting scroll hub 56) and a top surface 21 of the eccentric portion 22.

[0034] As mentioned above, during operation the spiral involute 54 of the orbiting scroll and the spiral involute of the fixed scroll 80 compress a refrigerant that is suctioned into the compression pockets at a suction gas pressure Ps and discharged at a discharge gas pressure Pd. While the suctioned gas is being compressed the pressure of the suctioned gas will increase and the amount of intermediate gas pressure Pi may vary as it is compressed. In general, the intermediate gas pressure Pi may be referred to as a variable gas pressure that is between the suction gas pressure Ps and the discharge gas pressure Pd. As will be explained in more detail below, an axial piston 100 may move in an axial direction based on the application of different intermediate gas pressures during operation. In some implementations, the axial piston 100 maintains axial compliance by making contact or engaging with the bottom surface 53 of the orbiting scroll plate 52 to force it upward or toward the fixed scroll 80. The amount of upward force exerted on the bottom surface 53 of the orbiting scroll plate 52 may depend on the various amounts of intermediate gas pressure acting with or on the axial piston 100.

[0035] In some implementations, the axial piston 100 has a cylindrical main 104 body with a top rim portion 102 and a bottom rim portion 120. In some examples, an alignment pin 140 may be pressed into a portion of the upper upward facing surface 236 of the main frame 26, and there is a corresponding hole 142 in the inner downward facing surface 127 of the top rim portion 102. The alignment pin 140 may be a small dowel pin or otherwise. Further, the alignment pin 140 may be disposed between a first seal 130 and suction gas cavity 214 in the radial direction. The hole 142 in the inner downward facing surface 127 has ample clearance for ease of assembly and allows the axial piston 100 to move up and down axially but ensures radial alignment. In other words, the alignment pin 140 allows axial movement, but restricts radial movement of the axial piston 100.

[0036] In some examples, the axial piston 100 also includes gas passages through which the intermediate pressure gas Pil from the compression chamber 34 passes through to a first back chamber 224. In some implementations, a first axial passage 202 may be disposed in the orbiting scroll plate 52 with an opening 201 to a compression chamber 34 at an upper end and an opening with a radial passage 204 in the orbiting scroll plate 52 at the lower end. The first axial passage 202 is in communication with the compression chamber 34 and the radial passage 204 so that intermediate gas pressure (Ps) from the compression chamber 34 may pass through the first axial passage 202 into the radial passage 204. The opening 201 is located such that during the orbit cycle, as the spiral involute 54 of the orbiting scroll 50 and the spiral involute 84 of the fixed scroll 80 move relative to one another, intermediate pressure gas Pil may pass into the opening 201, but the opening 201 is closed before the discharge exit is open. Accordingly, for example, the first axial passage 202 is a source for compressed suction gas, which is gas at an intermediate pressure Pil.

[0037] Further, the radial passage 204 may be disposed in the radial direction in the orbiting scroll plate 52. One end may be plugged with a plug 206. The radial passage 204 is open and in communication with the first axial passage 202 and a second axial passage 208. The diameter of the radial passage 204 may be greater than each of the first axial passage 202 and the second axial passage 208. In some examples the second axial passage 208 is disposed in the orbiting scroll plate 52 and has an opening 209 in the bottom surface 53 of the orbiting scroll plate 52. Further, the second axial passage 208 may be disposed at a greater distance in the radial direction from the drive shaft 20 than the first axial passage 202.

[0038] Additionally, in some implementations, a receiver cavity 108 may be disposed in a top surface 106 of the top rim portion 102 of the axial piston 100. The receiver cavity 108 may be a concave portion, depression or recession in the top surface 106 and may be circular or have a different shape that permits communication between the receiver cavity 108 and the opening 209 of the second axial passage 208 during the orbit cycle. That is, in some examples, the receiver cavity 208 is shaped such that all times during the orbiting motion of the orbiting scroll 50, the opening 209 of the second axial passage 208, which moves with the orbiting scroll 50 motion, is in communication with the receiver cavity 108, which is essentially static with respect to radial movement.

[0039] As further shown in Fig. 2, in the axial piston 100, an axial passage 110 may be disposed through the top rim portion 102, the cylindrical main body 104 and the bottom rim portion 120. A top opening of the axial passage 110 may be open to and in communication with a bottom of the receiver cavity 108. A bottom opening 112 of the axial passage 110 may be open to and in communication with the first back chamber 224. Accordingly, the gas that enters the first back chamber 224 is intermediate pressure gas Pil. That is, intermediate pressure gas Pil sourced from the compression chamber 34 enters the first axial passage 202 and passes into the radial passage 204, second axial passage 208, receiver cavity 108, axial passage 110 of the axial piston 100 and into the first back chamber 224. Accordingly,

[0040] During the orbit cycle, the pressure at the beginning of compression is low, but reaches a high level while still open to the intermediate pressure source. This high-low cyclic pressure is metered through a small opening 209 in the second axial passage 208 such that the resulting intermediate gas Pil in the first back chamber 224 is essentially a constant average for a given operating condition. In order to deliver the pressure to the first back chamber 224, the receiver cavity 108 may be placed in the top surface 106 of the top rim portion 102. The receiver cavity 108 may have a diameter which is large enough to ensure that the intermediate pressure source is always open, during the circular motion of the orbiting scroll. The depth of receiver cavity 108 may be minimal for the flow requirements. In general, the receiver cavity 108 diameter is larger than the orbit diameter, which is mathematically related to the involute geometry. That is, the diameter of the receiver cavity 108 may be based on the geometry of the spiral involute 54 of the orbiting scroll 50. [0041] As mentioned above, the axial piston 100 essentially can move up and down within the main frame 26. In some implementations, an outer surface 105 of the cylindrical main body 104 engages an inner structure 240 of the main frame 26, which may be round, circular or essentially cylindrical bore having a corresponding shape to the outer surface 105 of the cylindrical main body 104. The inner structure 240 may be concentric with respect to the drive shaft 20 and may be a precision bore for inserting or housing the axial piston 100. Accordingly, the surface of the inner structure is cylindrical and may have a shape and/or curvature corresponding with the outer surface 105 of the axial piston 100.

[0042] In some examples, a first seal 130 may be disposed within a first seal groove 131 disposed the outer surface 105 below the top rim portion 102 to engage with a portion of the inner structure 240 of the main frame 26. Additionally, a second seal 134 may be disposed within a second seal groove 135 of the outer surface 105 below the first seal 130. The second seal 134 may engage with a portion of the inner structure 240 of the main frame 26 and may be disposed in a same horizontal plane as the bottom rim portion 120.

[0043] In some examples, an inner facing surface 122 of the bottom rim portion 120 may be circular and may face inward and engage with an outer facing surface 242 of the main frame 26. The inner facing surface 122 and the outer facing surface 242 may be concentric and the inner facing surface 122 may essentially surround a portion of the outer facing surface 242. The outer facing surface 242 may be a circular portion of the main frame 26 and may correspond with the inner facing surface 122. Further, a third seal 238 may be disposed in a third seal groove 239 in the inner facing surface 122 of the bottom rim portion and may engage with the outer facing surface 242 of the main frame 26. Additionally, the third seal 238 and the second seal 134 may be in the same horizontal plane. In another example, the third seal 238 and corresponding third seal groove 239 may be disposed in the outer facing surface 242 of the main frame 26 instead of in the inner facing surface 122 of the bottom rim portion 120. In this instance, the seal disposed in a seal groove within the outer facing surface 242 may engage or contact the inner facing surface 122.

[0044] In some implementations, the first back chamber 224 is a volume underneath the bottom surface 124 of the bottom rim portion 120 and above the lower upward facing surface 244 of the main frame 26. For example, the bottom surface 124 may be a flat and/or smooth surface that may be circular and parallel to the lower upward facing surface 244 and bottom surface 53 of the orbiting scroll plate 52. Also, the lower upward facing surface 244 may be a flat and/or smooth surface that may be circular and parallel to the bottom surface 124 and bottom surface 53 of the orbiting scroll plate 52. Further, the bottom surface 124 of the bottom portion 120 may face the lower upward facing surface 244 and may be concentric. Accordingly, in some implementations, the first back chamber 224 exist in a gap between the lower upward facing surface 244 and the bottom surface 124 of the bottom rim portion 120. [0045] Further, in some examples, a second back chamber 226 that essentially contains intermediate pressure gas Pi2, which may be at a different pressure than the intermediate pressure gas Pil, exists between the outer periphery of the orbiting scroll hub 56 and the inner surface 103 of the cylindrical main body 104.

[0046] In some implementations, a radial exit passage 114 is disposed that extends in the radial direction through a lower portion of the main cylindrical body 104 that is open and in communication with the second back chamber 226 on one side. The radial exit passage 114 is open and in communication with a radial passage 246 of the main frame 26 through opening 115 of the radial exit passage 114 and through opening 247 of radial passage 246 of the main frame 26. The radial exit passage 114 may be disposed above the bottom rim portion 120 in the axial direction and below the eccentric portion 22 of the drive shaft 20. In some examples, at the end of the radial passage 246 opposite the opening 247 a plug 248 may be disposed. [0047] In some implementations, the radial exit passage 114 is greater than the radial passage 246 of the main frame 26. Accordingly, in some implementations, the opening 115 of the radial exit passage 114 is greater than the opening 247 of the radial passage 246 in the main frame 26. In other words, the radial exit passage 114 and the radial passage 246 of the main frame 26 may be circular and therefore the diameter of the opening 115 of the radial exit passage 114 is greater than the diameter of opening 247 of the radial passage 246 of the main frame 26. As mentioned above, during operation the axial piston 100 moves in the axial direction based on the intermediate pressure gas Pil is applied to the first back chamber 224. In some examples, the back pressure of the intermediate pressure gas Pil in the first back chamber 224 exerts upward force on the axial piston 100 pushing it up against the bottom surface 53 of the orbiting scroll plate 52. The volume of the first back chamber 224 may expand or contract based on the intermediate gas pressure Pil applied to the first back chamber 224. Additionally, in some examples, the axial piston 100 may rest on the lower upward facing surface 244 of the main frame 26, for example, when the first back chamber 224 does not have intermediate gas pressure Pil applied thereto when the compressor is not being operated, for example. Further, when the compressor is not running, it is possible that the axial piston 100 will slip down; even to rest on lower upward facing surface 244 or upper upward facing surface 236. This could occur as the pressures in the system equalize over time, after shutdown. Also, in some examples, based on the assembly clearances of diameters and alignment pins, the axial piston 100 could be making a small orbit motion during operation, but it would be negligible. [0048] The size or diameter of the opening 115 of the radial exit passage 114 is such that as the axial piston 100 moves in the axial direction, the radial exit passage 114 and the radial passage 246 of the main frame 26 may also be in communication with each other. In other words, in some implementations, the size of the opening 115 is greater than the size of the opening 247 to permit the passage of gas and/or a gas and oil mixture to pass through regardless of the axial position of the axial piston 100.

[0049] Further, a relief valve passage 250 may be disposed in a portion of the main frame 26 that may be below the orbiting scroll 50, above the bottom rim portion 120 of the axial piston 100 and in a same plane as a portion of the cylindrical main body 104 of the axial piston 100. The relief valve passage 250 may be circular and may be open to and in communication with the radial passage 246 of the main frame 26 at one end. A pressure relief valve 252 may be disposed at the other end of the relief valve passage 250. The pressure relief valve 252 may be a spring valve, or adjustment spring valve. Alternatively, a precision orifice may be disposed. The pressure relief valve may relieve pressure of gas and/or a gas and oil mixture, from the Pi2 gas pressure cavity into a suction gas cavity 214, which may contain gas at a suction pressure Ps. Further, depending on the operating condition of the system that the scroll compressor 1 is operating, the Pi2 gas pressure and suction gas pressure Ps can change significantly.

[0050] Further, as oil passes through the oil passage 23, the oil may enter a gap 57, which may be a third back chamber 228. That is, discharge pressure Pd may act to force oil into the oil passage 23. The oil may lubricate the orbiting scroll bearing 25, for example. This may be referred to as a differential pressure oil pump. The third back chamber 228 may be defined as a volume above the top surface 21 of shaft eccentric portion 22, below bottom surface 58 and inside or within the orbiting scroll hub 56. The Pd oil pressure may become a lower Pd2 pressure since the oil may creep or move through the orbiting scroll bearing 25 for lubrication. Near the lower end of the orbiting scroll bearing 25 the oil may enter the second back chamber 226 through an orbiting scroll bearing clearance orifice 138 (which may contain intermediate pressure Pi2). Oil and gas may flow through this orbital bearing clearance, which in some instances is an orbiting scroll bearing clearance orifice 138, since the second back chamber 226 is in communication with the pressure relief valve 252 inserted between the second back chamber 226 and the suction gas cavity 214. Therefore the fluid in the second back chamber 226 may start as oil with discharge pressure Pd2 with a small amount of refrigerant gas, but becomes intermediate pressure Pi2 because of metering into lower suction gas pressure Ps. The intermediate gas pressure Pi2 flow into suction gas Ps may contain a controlled amount of oil. The relationship among these pressures may be defined as: Pd > Pd2 > Pi2 > Pil > Ps.

[0051] The gas in the first back chamber 224 may then be contained between the second seal 134 and the third seal 238. The first seal 130 may also separate suction gas Ps from a small volume, which may be the cylindrical clearance between the axial piston 100 and the inner structure 240 of the main frame 26. The third seal 238 may separate intermediate pressure gas Pil in the first back chamber 224 from the intermediate pressure gas Pi2, which is in the second back chamber 226. The first seal 130, second seal 134 and third seal 238 may all be annular gasket.

[0052] Additionally, in some implementations, the top surface 106 of the top rim portion 102 may essentially be circular and concentric with the drive shaft axis 96. The top surface 106 may abut, engage and/or contact the bottom surface 53 of the orbiting scroll plate 52. The top surface 106 may be referred to as a piston thrust surface. The top surface 106 (piston thrust surface) supports the orbiting motion of the orbiting scroll 50 and transfers a component of the total back chamber force of the first back chamber 224 underneath the orbiting scroll 50. The top surface is perpendicular to the cylindrical main body 104. Accordingly, as mentioned above, the axial piston 100 may transfer the intermediate pressure Pil force of the first back chamber 224 to the top surface 106 to exert a force on the bottom surface 53 of the orbiting scroll plate 52. The diameter of the top surface 106 of the top rim portion 102 also provides a large area under the orbiting scroll 50 to minimize an overturning moment, which may be caused by the horizontal compression force, as shown in Fig. 6. In some examples, a radius of the top surface 106 is greater than a radius of the spiral involute 54 of the orbiting scroll 50 at its greatest radius. The top surface 106 may be a polished area and may be flat and parallel to the bottom surface 53 of the orbiting scroll plate 52.

[0053] Additionally, in some implementations, there is a clearance between the outer downward facing surface 126 of the top rim portion 102 and the upper upward facing surface 236 of the main frame 26. The outer downward facing surface 126 of the top rim portion 102 and the upper upward facing surface 236 of the main frame 26 may be flat, parallel, and may face one another. Further, the suction gas cavity 214 may be disposed in a portion of the upper upward facing surface 236 of the main frame. Further, an axial length of the outer edge 118 of the top rim portion 102 may be equal to an axial length of the inner edge 107 of the top rim portion 102. The outer edge 118 and the inner edge 107 of the top rim portion 102 may be circular and coaxial.

[0054] FIG. 3 illustrates an example of an isometric view of an axial piston of a scroll compressor according to some implementations. As shown in Fig. 3, the top rim portion 102 includes a receiver cavity 108, which may be circular and has a predetermined depth. The axial passage 110 extends downward through the cylindrical main body 104 from a bottom 109 or floor surface of the receiver cavity 108. As mentioned, the receiver cavity 108 is a small chamber with a bore that is large enough to surround and contain the exit hole or opening 209 of the second axial passage 208 during the orbit motion of the orbiting scroll 50. The depth of the receiver cavity 108 is minimal for gas flow requirements. In some examples and as mentioned above, the receiver cavity 108 diameter is larger than the orbit diameter, which is mathematically related to the scroll set (i.e., spiral involute 54 geometry of the orbiting scroll 50 and spiral involute 84 of the fixed scroll 80).

[0055] Additionally, the radial exit passage 114 may be disposed through a portion of the cylindrical main body 104 between the first seal groove 131 and the second seal groove 135. As mentioned above, the location of the radial exit passage 114 coincides with the radial passage 246 of the main frame 26 to allow for continuous passage communication regardless of the axial position of the axial piston 100. Fig. 3 further shows the outer edge 118 of top rim portion 102 and the inner edge 107 of the top rim portion 102. As shown in Fig. 3, the axial piston 100 is essentially a hollow cylinder with a top rim portion 102 having portions that extend inward in the radial direction and outward beyond the periphery of the cylindrical main body 104. The top rim portion 102 is essentially disk like and the top surface 106 may be smooth and flat and perpendicular to the central axis of the axial piston (i.e., drive shaft axis 96).

[0056] FIG. 4 illustrates an example of a top view of an axial piston of a scroll compressor according to some implementations. As shown in Fig. 4, the top rim portion 102 may be circular. Further, the inner facing surface 122 of the bottom portion 120 has a smaller diameter than the inner surface 103 of the cylindrical main body 104.

[0057] FIG. 5 illustrates an example of a cross-sectional view of an upper portion of a scroll compressor according to some implementations. Fig. 5 shows, for example, dimensions of some of the components of the scroll compressor according to some implementations. The dimensions referred to herein may be a distance or a diameter and may affect the areas of one or more of the first back chamber 224, second back chamber 226 and third back chamber 228. Dimension D1 may refer to a diameter of the inner facing surface 122 of the bottom rim portion 102 of the axial piston 100. Dimension D2 may refer to the diameter of the outer surface 105 of the cylindrical main body 104 of the axial piston 100. Dimension D3 may refer to a diameter of the inner edge 107 of the top rim portion 102. Dimension D4 may refer to the diameter of the outer edge 118 of the top rim portion 102. Dimension D5 may refer to a diameter of an inner surface of the orbiting scroll hub 56 of the orbiting scroll 50. Finally, dimension D6 may refer to a diameter of the inner surface 103 of the cylindrical main body 104. The relationship between Dl, D2, D3, D4, D5, and D6 may also be D4 > D2 > D6 > D3 > D1 > D5. In some implementations: Dl = 54.5 mm; D2 = 82 mm; D3 = 60 mm; D4 = 97 mm; D5 = 34 mm; and D6 = 70mm.

[0058] While Dl and D2 are identified as part of the axial piston 100, there are corresponding diameters with a small clearance in the main frame 26. Therefore, the axial piston 100 has a controlled axial movement in a vertical plane. The following statements may apply concerning the axial gas pressure forces being applied to the orbiting scroll 50 and axial piston 100. For example, the intermediate gas pressure Pil may be applied upward on axial piston in an area of D2-D1, which may define the first back chamber 224. With respect to the second back chamber 226: intermediate gas pressure Pi2 may be applied upward directly on orbiting scroll 50 on an area that may be defined as D3-D5; intermediate gas pressure Pi2 may be applied upward on the axial piston 100 on an area that may be defined as D6-D3; and intermediate gas pressure Pi2 may be applied downward on axial piston 100 on an area which may be defined as D6-D1. With respect to the third back chamber discharge pressure of oil Pd2 may be applied upward directly on orbiting scroll 50 in an area which may be defined as D5.

[0059] Additionally, equation EQ1 relates to the area of the first back chamber 224.

[0060] EQ1 Area of first back chamber = (D2 ^A 2 - D1 ^A 2) x p/4.

[0061] Equation EQ2 relates to the area of the second back chamber 226.

[0062] EQ2 Area of second back chamber = (D3 ^A 2 - D5 ^A 2) x p/4.

[0063] Equation EQ3 relates to the area of the third back chamber 228.

[0064] EQ3 Area of third back chamber = (D5 ^A 2) x p/4.

[0065] Equation EQ4 relates to an area y pushing upwards on axial piston 100.

[0066] EQ4 Area y = (D4 ^A 2 - D2 ^A 2) x p/4.

[0067] Equation EQ5 relates to an area z pushing upwards on axial piston 100. [0068] EQ5 Area z = (D6 ^A 2 - D3 ^A 2) x p/4.

[0069] Equation EQ6 relates to an area x pushing down on axial piston 100.

[0070] EQ6 Area x = (D3 ^A 2 - D1 ^A 2) x p/4.

[0071] The areas defined by the above equations may be optimized for performance, stability, and reliability. Further, the optimum areas for the first back chamber 224 and the second back chamber 226 may be derived or calculated from various parameters of the scroll compressor design, as well as the operating envelope of the heating, ventilation and air conditioning (HVAC) system that uses the scroll compressor 1.

[0072] FIG. 6 illustrates an example of a free-body diagram showing certain forces and components of a scroll compressor according to some implementations. Fig. 6 includes certain force vectors, moments and moment arms and distances of a compressor scroll according to some implementations. The following Table lindicates definitions of the forces, moments, moment arms and distances included in Fig. 6.

Table 1: [0073] For example, while forces in the axial Z direction are significant, in general a challenging design requirement is presented by the Fres horizontal gas compression force. This is because of its overturning moment, with arm dimension Zl. The basic design reaction is to apply an axial force on the orbiting scroll 50, which produces a critical contact due to the tip thust- force of spiral involute 54 tip to fixed scroll involute floor 81 Ftt between the outer involute sections. Rtt, the required radius needed to maintain stability counteracting the overturning moment of the orbiting scroll 50, is calculated based on the magnitude of the sum of forces and moments. The design is considered stable when the Rtt calculated is less than the available radius on the outer involutes of the orbiting scroll 50. In some examples, more stable designs are indicated by a smaller Rtt, but these tend to consume more power in friction. The optimized design results in Rtt being maximized but not exceeding the available radius on the orbiting scroll 50. Of course available Rtt changes between a minimum to a maximum, during the crank angle of compression. The axial piston 100 may provide an additional stability feature, with orbiting scroll 50 thrust-force produced by the axial piston 100 Fbt. However, this force is applied with the moment arm Rbt, which is considered the available radius of the axial piston 100, and the result is a significant increase in stability. It has the effect of applying an additional counteracting moment arm to minimize the overturning moment of the orbiting scroll 50. This addition of a focused moment arm reduces the requirement for applied axial force Ftt; which also reduces the power consumed. The axial piston 100 transfers the moment into the orbiting scroll 50, and this essentially reduces the required radius for stability, Rtt. The resulting design objective would be to gain the stability effect of the Fnet (Fbt) force, but minimize the excess. This is because of the thrust force and lubrication requirements, which could increase the power and/or affect reliability.

[0074] Based on the free-body diagram of Fig. 6 and the definitions of Table 1, the following equations may be derived.

[0075] Equation EQ7 relates to the sum of force Fz in the Z (axial) direction on the orbiting scroll 50.

[0076] EQ7 Ftt = Fnet - Fag + Fbc3 + Fbc2

[0077] Equation EQ8 relates to the sum mass M of the orbiting scroll 50 about Fsb.

[0078] EQ8 Fnet x Rbt = Fres x Zl - Ftt x Rtt

[0079] Equation EQ9 relates to a sum of force Fz on the axial piston 100.

[0080] EQ9 Fnet = Fbc 1 + Fsp - Fap

[0081] Equation EQ10 is a combination of EQ9 into EQ7 [0082] EQ10 Ftt = Fbc 1 + Fsp - Fap - Fag + Fbc3 +Fbc2

[0083] Equation EQ11 relates to the equivalent radius of Ftt force-distribution.

[0084] EQ11 Rtt = (Fres x Z1 - Fnet x Rbt)/Ftt

[0085] As mentioned, a significant challenge in scroll compressor technology is to ensure that an axial compliant scroll set operates in a stable condition, at all possible conditions in the envelope. The instability is generally caused by the large compression force Fres; and this is a resultant of vectors Ftg and Frg, which are 90 degrees apart in a horizontal plane. This requires that the spiral involute 54 tip of the orbiting scroll 50 maintains contact with the fixed scroll involute floor 81 and the spiral involute 84 of the fixed scroll 80 maintains contact with the orbiting scroll involute floor 51 throughout the 360 degree compression orbit. The force generated at these surfaces cycles from a high to low value, during the compression orbit, and creates the overturning moment. This presents the other significant challenge, which is to minimize excessive thrust force contact between the scroll set and the support underneath the orbiting scroll 50. These consume higher power as well as a reliability risk. As seen in Fig. 6, the large force Fres has a moment arm of Zl, which can be minimized within limits of the orbiting scroll bearing 25, to reduce the overturning moment. The second parameter to achieve this is the “R available” tip thrust moment arm of the orbiting scroll involute, and obviously maximizing this will increase stability. Along with this, a useful design parameter to express stability is “required radius”, which obviously must remain less than available radius. The axial piston 100 addition of Fnet force at the radius of Rbt, provides significantly greater stability; and this can yield a reduction in the maximum applied thrust force on the orbiting scroll. In conclusion, a taller spiral involute 54 of the orbiting scroll 50 may produce a higher displacement and capacity. However, an increase in Zl then increases the overturning moment (instability). It is therefore apparent why extending the effective stability is valuable.

[0086] Assembly of the scroll compressor 1 may be based on press fit alignment and securing of the bearing components, such as the lower bearing 94, main bearing 24, axial piston 100, and the scroll set. The drive shaft 20, counterweight 60, and rotor sub-assembly could be inserted into the center shell, containing the stator 16 and lower bearing 94. The main frame 26 may be inserted over the main bearing 24 and pressed into the center shell 4 until the main frame 26 rests on an edge of the case (denoted at 12 in Fig. 1, for example). The first seal 130, second seal 134 may be inserted into the axial piston 100 and then the axial piston 100 may be inserted into the inner structure 240 or bore of the main frame 26 and the alignment pin 140 may be aligned. The Oldham coupling 70 and orbiting scroll 50 may then be inserted into position. The fixed scroll 80 may be aligned and assembled with respect to the Oldham coupling 70 and the main frame 26.

[0087] FIG. 7 illustrates an example of a detailed cross-sectional view of an upper portion a compressor according to some implementations. Radial compliance in scroll technology allows the scroll set (e.g., the orbiting scroll 50 and fixed scroll 80) to establish the eccentric offset of the shaft journal for the orbiting scroll 50 by maintaining contact of the spiral involute of the orbiting scroll 54 with the fixed scroll involute floor 81 and contact of the spiral involute of the fixed scroll 84 with the orbiting scroll involute floor 51 throughout compression. The techniques discussed herein provide radial compliance to produce a relatively constant involute wall contact regardless of operating condition and speed.

[0088] In general, the implementation of the scroll compressor of Fig. 7 includes the same or similar elements and features as described above and therefore these elements and features may not be described below for the sake of brevity. Not all of the similarities and differences between the implementations shown above and described with respect to Fig. 7 are discussed or referenced herein. A difference, for example, is that a counterweight 60 disposed below the main frame 26 is not utilized. Further, in the example shown in Fig. 7, a counterweight 800 and a counterweight guide plate 900 are disposed within the cylindrical main body 704 of the axial piston 700. Further, a slider block 300 may be disposed on the eccentric portion 22 of the drive shaft 20. Another difference may be that the cylindrical main body 104, bottom rim portion 120 and top rim portion 102 of the axial piston 100 shown in Fig. 2, for example, may be a uniform or whole structure or one piece. In the example shown in Fig. 7, a piston thrust surface 702 may be a separate part or component from the structure of the axial piston 700 that includes the cylindrical main body 704 and bottom rim portion 720.

[0089] The counterweight guide plate 900 may also include a spring 950, such as a ball spring. The counterweight 800 may be attached to the slider block 300, which may be a radial compliant slider block 300 having a drive flat 306 (not shown in this view) on an inner surface 301 thereof, and the counterweight guide plate 900 may be attached to the drive shaft 20 below the slider block 300. Along with a spring force, the radial compliance mechanisms (e.g., slider block 300, counterweight 800 and counterweight guide plate 900) can maintain the scroll involute flank contact force (such as the contact of the spiral involute 54 tip of the orbiting scroll 50 with the fixed scroll involute floor 81 and contact of the spiral involute 84 of the fixed scroll 80 maintains with the orbiting scroll involute floor 51) relatively constant, regardless of speed. The examples shown herein include disposing a main mass structure 838 of the counterweight 800 to a higher position, closer to the mass of the orbiting scroll 50, as well as a spring 950 between the counterweight 800 and the counterweight guide plate 900, that can be adjusted during assembly. The shape and/or design of the counterweight 800 and counterweight guide plate 900 are designed to fit within the cylindrical main body 704 of the axial piston 700. Since the piston thrust plate 702 of the axial piston 700 may be a separate element or component from the remaining portion(s) of the axial piston 700, this allows the counterweight 800 and counterweight guide plate 900 to be disposed within the axial piston 700.

[0090] As shown in Fig. 7, the drive shaft 20 has an eccentric portion 22 which has a smaller diameter than a diameter of the main portion of the drive shaft 20. Additionally, an intermediate diameter portion 320 of the drive shaft 20 may be between the eccentric portion 22 and the remaining portion of the drive shaft 20 in the axial direction. At the intermediate diameter portion 320, an outward facing surface 322 may face outward and have an axial dimension that is equal to a thickness of the base 902 of the counterweight guide plate 900. A bore 901 of the counterweight guide plate 900 attaches to the drive shaft 20 and a bore surface 904 may contact and abut the outward facing surface 322 of the drive shaft 20. Further, a first intermediate upward facing surface 324 that is perpendicular to the outward facing surface 322 (in cross-sectional view) may abut or contact a portion of the bottom surface 920 of the counterweight guide plate 900, which is parallel to the upward facing surface 324. In some examples, the counterweight guide plate 900 may be press fit on the outward facing surface 322.

[0091] In some examples, as mentioned above, slider block 300 may be disposed on the eccentric portion 22. An orbiting scroll bearing 25 may be disposed around the outer surface 302 of the slider block 300. A second intermediate upward facing surface 326 may be parallel to the first intermediate surface 324 and may be a surface upon which a bottom surface 304 of the slider block and a portion of the bottom surface 806 of the counterweight 800 contact or abut. The slider block 300 may essentially have a circular profile and may be essentially cylindrical and hollow. The slider block 300 may include a drive flat (not shown in this view), which is an essentially flat portion of the inner surface 301 of the slider block 300. The drive flat 306 may correspond to a flat portion of the shaft eccentric portion 22 of the drive shaft 20. Further, the relationship of the drive flat 306 to the eccentric offset may be known as a drive angle. In some implementations, the inner surface 301 may be curved and the curvature may correspond with a curvature of an outer surface of the eccentric portion 22 of the drive shaft 20. The slider block 300 may be press fit into the compliant counterweight 800, into an inner surface 804 of the bore 802, for example, with radial alignment related to the drive flat 306 of the slider block 300, for example.

[0092] The counterweight 800 may be disposed on the slider block 300 such that an inner surface 804 of the bore 802 of the counterweight 800 may be disposed around and in contact with an outer surface 302 of the slider block 300. In some examples, the counterweight 800 may be press fit onto the outer surface 302 slider block 300. Additionally, a portion of the bottom surface 806 of the counterweight 800 may contact or abut a portion of the top surface 903 of the base 902 of the counterweight guide plate 900. The bottom surface 806 of the counterweight 800 and the base 902 of the counterweight guide plate 900 may be parallel and flat.

[0093] Fig. 7 further shows an axial piston 700, which is essentially cylindrical and hollow and may include a cylindrical main body 704, bottom rim portion 720 and piston thrust plate 702. An axial passage 710 is disposed through the cylindrical main body 704. A bottom opening 712 of the axial passage 710 may be open to and in communication with the first back chamber 224. A top opening of the axial passage 710 opens through the top surface 711 of the cylindrical main body 704.

[0094] The piston thrust plate 702 may essentially be a ring shape, disk, or other circular structure having a top surface 706 that is flat and parallel to the bottom surface 53 of the orbiting scroll plate 52. In some implementations, the piston thrust plate 702 may have the same dimensions as the top portion 102 of the axial piston 100, such as the inner edge 107, outer edge 118, inner downward facing surface 127 and outer downward facing surface 126. For example, the dimensions and the relationships between the dimensions Dl, D2, D3, D4 and D6 described above may also be the same for the axial piston 700. Additionally, the inner downward facing surface 727 and outer downward facing surface 726 may be flat and parallel to the top surface 706. Further, the inner edge 707 and outer edge 718 may be flat and perpendicular to the top surface 706 (in cross-section). Further, an axial length of the outer edge 718 of the piston thrust surface 702 may be equal to an axial length of the inner edge 707 of the piston thrust surface 702. The outer edge 718 and the inner edge 707 of the piston thrust surface 102 may be circular and coaxial. Accordingly, the relationships and equations described above with respect to the axial piston 100 also apply to the implementation shown in Fig. 7 implementing the axial piston 700. [0095] Further, the separate piston thrust surface 702 and/or cylindrical main body 704 must be radially aligned with the cylindrical main body 704 of the axial piston 700 to ensure that the receiver cavity 708 is aligned with the second axial passage 208, as well as the radial exit passage 714 for intermediate pressure gas Pi2 is aligned with the radial passage 246. In some examples, a dowel alignment pin can be pressed into a portion of the main frame 26 then engage into a hole within the piston thrust plate 702 to ensure correct radial alignment.

[0096] The top surface 706 may be a smooth and planar surface that supports a thrust force of the axial piston 700. Disposed within the top surface 706 is a receiver cavity 708 that is in communication with the second axial passage 208 and an axial passage 717 of the piston thrust plate 702. In some examples, the bottom surface 741 of the piston thrust plate 702 includes an annular groove 740 that engages with top portion and top surface 711 of the cylindrical main body 704. In some examples, the top surface 711 of the cylindrical main body 704 supports and contacts the groove 740 portion of the bottom surface 741. Further, the inward facing edge 742 of the groove contacts or abuts a portion of the outer surface 705 of the cylindrical main body 704. Also, in some examples, the outward facing edge 744 of the annular groove 740 contacts or abuts a portion of the inner surface 703 of the cylindrical main body 704. In some implementations, the piston thrust plate 702 is press fit onto the cylindrical main body 704. Accordingly, upon assembly, the lower or bottom opening 719 of the axial passage 717 of the piston thrust plate 702 is in communication with and is open to the top opening 713 of the axial passage 710. In some examples, the top surface 706 of the piston thrust plate 702 is lubricated with the lubricant, such as oil. Generally, as the Pd2 oil is drawn into the second back chamber 226, refrigerant that is mixed with this, converts back to a gas. This oil/gas mix then flows into the lower pressure cavities. Examples are the radial exit passage 714, which then exits into the Ps suction gas chamber, through the pressure relief valve 252. Along with this, some of the oil will pass into a Ps suction gas chamber, between the bottom surface 53 of the orbiting scroll plate 52, and the top surface 706 of the axial piston thrust plate 702.

[0097] As illustrated in Fig. 7, the outer periphery surface of each of the counterweight 800 and counterweight guide plate 900 in the radial direction are within the radial dimensions of the inner surface 703 of the cylindrical main body 704 of the axial piston 700. For example, with respect to the drive shaft 20, the radial distance of the outer edge 905 of the base 902 of the counterweight guide plate 900 is less than the radial distance of the inner surface 703 of the cylindrical main body 704. Additionally, for example, with respect to the drive shaft 20, a maximum radial distance of the outward facing curved surface 842 is less than the radial distance of the inner surface 703 of the cylindrical main body 704. Further, a plane including a bottom surface 920 of the counterweight guide plate 900 is above the bottom rim portion 720 of the axial piston 700 and a plane including the top surface 711 of the cylindrical main body 704 is above an uppermost top surface 840 of the counterweight 800. Accordingly, the counterweight 800 and counterweight guide plate 900 may be disposed within the axial piston 700 in the radial and axial dimensions. Also, the main mass 838 of the counterweight 800 may essentially be in line with the orbiting scroll bearing 25.

[0098] Fig. 7 also shows the first axial passage 202, radial passage 204 and second axial passage 208, which communicate intermediate pressure gas Pil to the receiver cavity 708 of the piston thrust plate 702. Accordingly, intermediate pressure gas Pil may be passed or communicated to the first back chamber 224 from the compression chamber 34 through the first axial passage 202, radial passage 204, second axial passage 208, receiver cavity 708, axial passage 717 and axial passage 710.

[0099] Fig. 8 illustrates an example of a perspective view of a counterweight of a compressor according to some implementations. Fig. 9 illustrates an example of a perspective view of a counterweight of a compressor according to some implementations. In some implementations, the counterweight 800 includes a ring-shaped structure 808, a main mass structure 838 and a lower mass structure 810.

[00100] The ring-shaped structure 808 is essentially round or disk-shaped and includes a bore 802 having an inner surface 804 of the bore 802 and an outer surface 805. The inner surface 804 of the bore 802 engages with or contacts the outer surface 302 of the slider block 300.

[00101] The lower mass structure 810 may be a curved, rounded and/or disk-shaped portion that may be disposed essentially 180° or wrap essentially 180° around the outer surface 805 of the ring-shaped structure 808 and protrudes outwardly. The outer surface 812 of the lower mass structure 810 may be curved and smooth and the radial thickness of the lower mass structure 810 decreases gradually and symmetrically with respect to a vertical plane bisecting the lower mass structure 810. In some examples, an extension member 814 is disposed on a portion of the outer surface 812 of the lower mass structure 810. In some examples, the extension member 814 is disposed symmetrically with respect to the plane bisecting the lower mass structure 810, such that the plane also bisects the extension member 814. Further, a contact protrusion 816 may extend or protrude upward from the extension member 814. The contact protrusion 816 may be a bump, rail, ridge or other member. An outward face 818 of the extension member 814 may be flat and extend along the width of the contact protrusion 816.

[00102] Further, a bottom surface 806 of the ring-shaped structure 808 and the lower mass structure 810 may be flat and parallel to the top surface 903 of the base 902 of the counterweight guide plate 900. Further, in some implementations, there may be a gap between the top surface 803 of the ring-shaped structure 808 and the orbiting scroll hub 56 in the axial direction. Also, as shown in the figures, corners or intersection of the respective faces or surfaces may be curved, rounded or beveled. The lower mass structure 810 may also include a first face of the lower mass structure 820 and a second face of the lower mass structure 822 which are end faces of the curved protrusion or curved wrap of the lower mass structure 810. The first face of the lower mass structure 820 and the second face of the lower mass structure 822 may be flat and smooth and man be in a same vertical plane.

[00103] In some implementations, the main mass structure 838 may be a curved, rounded and/or disk-shaped portion that may be disposed essentially 180° or wrap essentially 180° around and above the lower mass structure 810. The main mass structure 838 may protrude outward further than the lower mass structure 810 in the radial dimension and extend higher in the axial dimension. Further, a lower surface of the main mass structure 838 may be disposed over and above a top edge 914 of an L-shaped structure 912 of the counter weight guide plate 900, which is explained in more detail below. A radial thickness of the main mass structure 838 may decrease gradually and symmetrically with respect to the vertical plane bisecting the main mass structure 838 and the lower mass structure 810. The inner curved surface 844 may have a constant radius and may extend essentially 180°.

[00104] The top surface uppermost top surface 840 of the main mass structure 838 may also be flat and parallel to the bottom surface 53 of the orbiting scroll plate 52. Additionally, in some implementations there may be a gap between the orbiting scroll hub 56 and the inner curved surface 844 of the main mass 838 of the counterweight 800 in the radial direction. The curvature of the inner curved surface 844 may correspond with the curvature of the outward facing curved surface 842. Further, the bore 802 may not be coaxial or concentric with the inner curved surface 844 and may be offset. In some implementations, the main mass structure 838 may also include a first face of the main mass structure 850 and a second face of the main mass structure 852 which are end faces of the curved protrusion or curved wrap of the main mass structure 838. The first face of the main mass structure 850 and the second face of the main mass structure 852 may be flat and smooth and man be in a same vertical plane as each other and may both be in a same vertical plane as the first face of the lower mass structure 820 and the second face of the lower mass structure 822.

[00105] FIG. 10 illustrates an example of a perspective view of a counterweight guide plate of a scroll compressor according to some implementations. In some examples, the counterweight guide plate 900 includes a base 902 having a wide portion 906 with a flat top surface 908 and a flat bottom surface 920 that are parallel to one another. The wide portion 906 of the base 902 extends outward in the radial direction from the bore 901 and the outer edge 905 of the wide portion 906 may be curved accordingly. In other words, in some examples, the wide portion 906 extends around a portion of the circumference of the bore 901 and extends outward and may fan outward. Also, the bottom surface 920 may be parallel to the first intermediate upward facing surface 324, which is circular.

[00106] Additionally, in some examples, an L-shaped structure 912 or C-shaped structure may be disposed extending off a portion of the base 902 that is opposite the wide portion 906 of the base 902 across the bore 901. The L-shaped structure 912 may include a vertically extending portion 916 and a top edge 914 extending inward from a top portion of the vertically extending portion 916 that is above the base 902 and extends toward the drive shaft 20. In some examples, the top edge 914 has a flat inner face 918 (see Fig. 7) that faces a portion of the outer surface 812 of the lower mass structure 810 of the counterweight 800 that is above the contact protrusion 816 in the axial direction. Additionally, in some examples, a bottom facing surface 922 of the top edge 914 faces downward and may be flat and parallel to the top surface 908 of the base 902.

[00107] Some implementations of the counterweight guide plate 900 also include a hole 924, which may be a bore or a passage or the like, through the vertically extending portion 916. The hole 924 may house a spring 950, which may be a threaded ball spring with a rounded end 951 that may contact the outward face 818 of the extension member 814. In some examples, the spring 950 may be adjusted for balance.

[00108] In some instances, there may be a gap between the bottom facing surface 922 and the contact protrusion 816. Further, the bottom facing surface 922 may contact the contact protrusion 816 of the counterweight 800. The bottom facing surface 922 may provide an “up stop” for the counterweight 800 on the slider block 300 that may limit tilting and edge loading of the slider block 300 with respect to the orbiting scroll bearing 25. The bottom facing surface 922 and the contact protrusion 816 of the counterweight 800 may prevent the compliant counterweight 800 and slider block 300 from an adverse compliant counterweight 800 rotation, due to high speed centrifugal force of the orbiting, for example. The centrifugal force of the orbiting scroll 50 mass could cause problems, such as instability, as well as transient conditions of the scroll compressor 1 operation. This reliability feature is especially important at the highest operating speed. Accordingly, these surfaces (bottom facing surface 922 and the contact protrusion 816) stabilize the slider block 300 and one purpose is to maintain strict vertical orientation of the slider block 300. This strict orientation prevents cross loading in the orbiting scroll bearing 25 at high speeds due to reacted moment on the counterweight 800 and slider block 300 assembly. Further, by applying the balanced counterweight 800 to the slider block 300, and counterweight guide plate 900 attached to the drive shaft 20 as disclosed herein the compressor can achieve essentially constant involute flank contact from low to high speeds, for example.

[00109] As mentioned above, the slider block 300 is disposed in the bore 802 of the counterweight 800. In some implementations, with respect to alignment, the slider block 300 axis and stabilizing surfaces (i.e., the bump or contact protrusion 816 and bottom facing surface 922) must be perpendicular. That is a horizontal plane including a top surface of the contract protrusion 816 is perpendicular to an axis of the slider block 300. Since, for example, the counterweight 800 is attached to the slider block 300, the stabilization caused by the interface, contact, or abutment of the bump or contact protrusion 816 and the bottom facing surface 922 of the counterweight guide plate 900 may prevent harmful tilting of the slider block 300 inside the orbiting scroll bearing 25, which may occur at high speeds due to excessive centrifugal force, for example. Accordingly, a top surface of the contact protrusion 816 may provide a line of contact or surface of contact for the bottom facing surface 922 at high speeds. For instance, the line of contact of the contact protrusion 360 may be as far radially outward and away from the slider block 300 as possible to provide the best stabilization.

[00110] Also, in some examples, the stabilizing surfaces (i.e., the bump or contact protrusion 816 and bottom facing surface 922) may be below the top surface of the ring-shaped structure 808 of the counterweight 800 in the axial direction. Further, the respective interfaces or comers of the respective surfaces of the counterweight and the counterweight guide plate may be rounded, smooth, or may be squared.

[00111] FIG. 11 illustrates an example of a top view of a piston thrust plate of a compressor according to some implementations. FIG. 12 illustrates an example of a top view of a portion of an axial piston of a compressor according to some implementations. Fig. 11 illustrates a top view of the piston thrust plate 702 showing the top surface 706, receiver cavity 708 and the axial passage through the piston thrust plate 702. Fig. 12 shows, for example, an upward facing surface 721 of the bottom portion 720 of the axial piston 700. Fig. 12 also shows the top opening of the axial passage 710 through the cylindrical main body 704.

[00112] FIG. 13 illustrates an example of a slider block of a compressor according to some implementations. As shown and mentioned above, the slider block 300 may essentially have a circular profile and may be essentially cylindrical and hollow. The slider block 300 has an outer surface 302 and a bottom surface 304, which is essentially circular. The slider block 300 may also include a drive flat 306, which is an essentially flat portion of the inner surface 301 of the slider block 300. The drive flat 306 may correspond to a flat portion of the shaft eccentric portion 22 of the drive shaft 20. Further, the relationship of the drive flat 306 to the eccentric offset may be known as a drive angle.

[00113] FIG. 14 illustrates an example of an isometric view in cross-section of portions of a scroll compressor according to some implementations. Fig. 14 shows the main frame 26, drive shaft 20, axial piston 700 including the main cylindrical body 704, piston thrust plate 702, Oldham coupling 70, orbiting scroll 50 and fixed scroll 80 among other elements that are not specifically referenced with respect to the description of Fig. 14. Fig. 14 further shows the counterweight 800 and counterweight guide plate 900.

[00114] With respect to assembly, the slider block 300 may be aligned and pressed onto the counterweight 800. The counterweight 800 and counterweight guide plate 900 may then be assembled with a fixture. The adjustable spring force may be set by adjusting the spring 950. The drive shaft 20 may be placed upside down in a fixture and the rotor 18 with a lower counterweight may be heat shrunk or cold-pressed into the aligned position. The first seal 130 and the second seal 134 may then be assembled into the axial piston 700. The up-right rotor- shaft assembly could then be placed into a fixture which supports the end of the drive shaft 20 and aligns the lower counterweight. The main frame 26 and axial piston 700 sub-assembly could then be inserted over the shaft main journal, to a fixture to support the lower perimeter of the main frame 26. The thrust plate could then be pressed onto the axial piston 700. The main frame 26, drive shaft 20, piston thrust plate 702, rotor sub-assembly could be inserted into the case, containing the lower bearing 24 member. The above sub-assembly could then be press fit together with the lower cap 6 assembly. Then, the Oldham coupling 70 and orbiting scroll 50 could be aligned into position. A fixture could preload the spring 950 such that the orbiting scroll 50 can be inserted over the slider block 300. Subsequently, the fixed scroll could be aligned and assembled to the Oldham coupling 70 and main frame 26. [00115] FIG. 15 illustrates an example of a detailed cross-sectional view of an upper portion a compressor according to some implementations. In general, the implementation of the scroll compressor of Fig. 15 includes the same or similar elements and features as described above with respect to Fig. 7 and therefore these elements and features may not be described below for the sake of brevity. For example, the implementation shown in Fig. 15 includes the counterweight 800, counterweight guide plate 900, slider block 300, orbiting scroll 50, fixed scroll 80, main frame 26, drive shaft 20, eccentric portion 20, among other elements that are described above. In the implementation shown in Fig. 15, however, the axial piston 1400 is different from the axial piston 100 and axial piston 700. Additionally, some elements may be the same or different as described above but are not specifically mentioned here for brevity. [00116] A difference between the axial piston 100 and the axial piston 1400 is the top portion 1402 does not include an inward protruding rim. In other words the inner surface 1403 of the cylindrical main body 1404 extends continuously and may contact the bottom surface 53 of the orbiting scroll plate 52. That is the inner surface 1403 and the top surface 1406 of the axial piston 1400 intersect one another and are perpendicular to one another (in cross-section). [00117] Further, disposed in the top surface 1406 of the top portion 1402 is a receiver cavity 1408 that is in communication with the second axial passage 208 of the orbiting scroll plate 52. As mentioned above, the second axial passage is in communication with the radial passage 204, which is in communication with the first axial passage 202, which is a source of intermediate pressure gas Pil from the compression pocket 34. The intermediate pressure gas Pil passes to the first back chamber 224, which is between the lower upward facing surface 244 of the main frame 26 and the bottom surface 1424 of the bottom portion 1420.

[00118] FIG. 16 illustrates an example of a top view of an axial piston of a compressor according to some examples. Fig. 16 shows the upward facing surface 1421 of the bottom portion of the 1420 of the axial piston 1400. Additionally, the inner facing surface 1422 of the bottom portion 1420 is shown extending inward in the radial direction from the inner surface 1403 of the cylindrical main body 1404.

[00119] FIG. 17 illustrates an example of a cross-sectional view of an upper portion of a scroll compressor according to some implementations. The dimensions referred to herein may be a distance or a diameter and may affect the areas of one or more of the first back chamber 224, second back chamber 226 and third back chamber 228. Dimension D1 may refer to a diameter of the inner facing surface 1422 of the bottom rim portion 1420 of the axial piston 1400. Dimension D2 may refer to the diameter of the outer surface 1405 of the cylindrical main body 1404 of the axial piston 1400. Dimension D4 may refer to the diameter of the outer edge 1418 of the top rim portion 1402. Dimension D5 may refer to a diameter of an inner surface of the orbiting scroll hub 56 of the orbiting scroll 50. Finally, dimension D6 may refer to a diameter of the inner surface 1403 of the cylindrical main body 1404. In some implementations: D1 = 54.5 mm; D2 = 82 mm; D4 = 97 mm; D5 = 34 mm; and D6 = 70 mm. [00120] In comparison to implementations using the axial piston 100 or axial piston 700, implementations using axial piston 1400 may increase the second back chamber 226, which means that the second back chamber 226 now is exposed to a larger area against the bottom surface 53 of the orbiting scroll plate 52. The following equations relate to the implementation using axial piston 1400.

[00121] The following equations relate to the first back chamber 224, second back chamber 226 and third back chamber 228 pushing upwards on the orbiting scroll 50.

[00122] Equation EQ12 relates to the area of the first back chamber 224

[00123] EQ12 Area of first back chamber = (D2 ^A 2 - D1 ^A 2) x p/4.

[00124] Equation EQ13 relates to the area of the second back chamber 226.

[00125] EQ13 Area of second back chamber = (D6 ^A 2 - D5 ^A 2) x p/4.

[00126] Equation EQ14 relates to the area of the third back chamber 228.

[00127] EQ14 Area of third back chamber = D5 ^A 2 x p/4

[00128] Equation EQ15 relates to area y pushing up on axial piston 1400.

[00129] EQ15 Area y = (D4 ^A 2 - D2 ^A 2) x p/4

[00130] Equation EQ16 relates to area x pushing down on axial piston 1400.

[00131] EQ16 Area x = (D6 ^A 2 - D1 ^A 2) x p/4

[00132] The intermediate pressure Pi2 upward on the orbiting scroll 50 defined as (D6-D5) is an increased area. So, it can be concluded that second back chamber 226, with intermediate gas pressure Pi2 has a greater effect on the axial force applied to the orbiting scroll 50 in an implementation using axial piston 1400 compared to an implementation using axial piston 100. In addition, the first back chamber 1 with intermediate pressure gas pressure Pil has a lesser effect on the applied axial force, because of the removal of the D3 dimension; which cancelled much of the downward force against the first back chamber 224.

[00133] The implementation using axial piston 1400 and the counterweight 800 and counterweight guide plate 900, maintains the pressures in the back chambers the same as an implementation using axial piston 100 without the counterweight 800 and counterweight guide plate 900, but the areas affected by these pressures have changed; therefore the forces have changed. For example, the upward force of the axial piston 1400 against the orbiting scroll 50 is reduced compared to an implementation using axial piston 100. Additionally, using the axial piston 1400, the total force applied to the orbiting scroll 50 is more dependent on the operating condition within the system.

[00134] With respect to assembly, the slider block 300 may be aligned and pressed onto the counterweight 800. The counterweight 800 and counterweight guide plate 900 may then be assembled with a fixture. The adjustable spring force may be set by adjusting the spring 950. The drive shaft 20 may be placed upside down in a fixture and the rotor 18 with a lower counterweight may be heat shrunk or cold-pressed into the aligned position. The first seal 130 and the second seal 134 may then be assembled into the axial piston 700. The up-right rotor- shaft assembly could then be placed into a fixture which supports the end of the drive shaft 20 and aligns the lower counterweight. The main frame 26 and axial piston 700 sub-assembly could then be inserted over the shaft main journal, to a fixture to support the lower perimeter of the main frame 26.

[00135] The counterweight guide plate 900 could be press fit onto the first intermediate upward facing surface 324. The thrust plate could then be pressed onto the axial piston 700. The main frame 26, drive shaft 20, piston thrust plate 702, rotor sub-assembly could be inserted into the case, containing the lower bearing 24 member. The above sub-assembly could then be press fit together with the lower cap 6 assembly. Then, the Oldham coupling 70 and orbiting scroll 50 could be aligned into position. A fixture could preload the spring 950 such that the orbiting scroll 50 can be inserted over the slider block 300. Subsequently, the fixed scroll could be aligned and assembled to the Oldham coupling 70 and main frame 26.

[00136] 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.

[00137] 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.