A compressor including a drive shaft assembly and a method for assembling the compressor.

Abstract

A compressor system includes a compressor housing and a drive shaft rotatably supported within the compressor housing. The compressor system further includes: an impeller that imparts kinetic energy to incoming refrigerant gas upon rotation of the drive shaft; a thrust disk coupled to the drive shaft; and a bearing assembly mounted to the compressor housing. The impeller includes an impeller bore having an inner surface, and the thrust disk includes an outer disk and a hub. The bearing assembly rotatably supports the outer disk of the thrust disk. The hub is disposed within the impeller bore and includes an outer surface that contacts the inner surface of the impeller bore. A first contact force between the outer surface of the hub and the inner surface of the impeller bore increases with increasing rotational speed of the drive shaft.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. nonprovisional patent application serial number 16 / 946,173, filed June 9, 2020, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The field of this disclosure generally relates to drive shaft assemblies for compressors, and more particularly to drive shaft assemblies including thrust discs and impellers used in compressors. Background Technology

[0004] Recent commercially available CFC-free refrigerant compositions, such as R134A, are characterized by lower densities compared to previously used CFC or HCFC refrigerants, such as R12. Therefore, air conditioning systems must handle larger volumes of CFC-free refrigerant compositions to provide comparable cooling capacity compared to CFC or HCFC refrigerants. To handle larger volumes of refrigerant, the gas compressor design can be modified to handle the refrigerant at higher operating speeds and / or operate with higher efficiency.

[0005] Centrifugal compressors using continuous dynamic compression offer at least several advantages over other compressor designs, such as reciprocating compressors, rotary compressors, scroll compressors, and screw compressors that use positive displacement compressors. Compared to at least some positive displacement compressor designs, centrifugal compressors offer numerous advantages, including less vibration, higher efficiency, a more compact structure and associated lighter weight, as well as higher reliability and lower maintenance costs due to a fewer number of wear-prone parts. The large-capacity cooling systems of centrifugal compressors allow the drive shaft to rotate at high speeds to transfer power from the motor to the impeller, thus kinetic energy to the incoming refrigerant. To mitigate the challenges associated with high-speed drive shafts, centrifugal compressors typically require relatively tight tolerances and high manufacturing precision. Additionally, other types of mechanical systems, such as motors, pumps, and turbines, also require drive shafts to rotate at high speeds. As is known to those skilled in the art of these types of rotating machinery systems, loosening and misalignment of components mounted to the drive shaft can occur during operation, resulting in unbalanced loads that cause vibration, subjecting the drive shaft to cyclic stress loads, leading to reduced service life and premature failure, particularly premature failure of bearings and seals.

[0006] Centrifugal compressors include one or more bearing assemblies that support and maintain alignment with a drive shaft. In a typical centrifugal compressor, components, such as the impeller and thrust disc, are individually connected to the drive shaft using friction fits, such as press fits or contraction fits. The drive shaft, impeller, and thrust disc, rotating at high speeds, generate centrifugal forces that increase with increasing rotational speed. These centrifugal forces are radially oriented away from the axis of rotation, pulling the components outwards away from the drive shaft and loosening the friction fit connections. Furthermore, the inertia of the components, particularly the radial distribution of their mass extending away from the axis of rotation, contributes to further loosening of the friction fits with the drive shaft. This loosening of the connections generates eccentric loads, causing the center of mass of the mounted components to misalign with the axis of rotation of the drive shaft. The effects of these eccentric loads are further amplified at high rotational speeds, leading to increased wear vibrations and potentially increased system downtime.

[0007] The design of mounting components on high-speed drive shafts presents a continuous challenge in maintaining a frictional fit between the drive shaft and the components. Furthermore, maintaining alignment of the component's center of gravity with the drive shaft's axis of rotation during high-speed operation helps avoid eccentric loads that could cause vibrations that could damage components of the centrifugal compressor.

[0008] This background section is intended to introduce the reader to various aspects of the art that may relate to the aspects described below and / or claimed in this disclosure. This discussion is intended to help provide the reader with background information to better understand the various aspects of this disclosure. Therefore, it should be understood that these statements are to be understood from this perspective and not as an admission of prior art. Summary of the Invention

[0009] In one aspect, the compressor system includes a compressor housing and a drive shaft rotatably supported within the compressor housing. The compressor system also includes: an impeller that imparts kinetic energy to incoming refrigerant gas when the drive shaft rotates; a thrust disk coupled to the drive shaft; and a bearing assembly mounted to the compressor housing. The impeller includes an impeller bore having an inner surface, and the thrust disk includes an outer disk and a hub. The bearing assembly rotatably supports the outer disk of the thrust disk. The hub is disposed within the impeller bore and includes an outer surface of the hub that contacts the inner surface of the impeller bore. A first contact force between the outer surface of the hub and the inner surface of the impeller bore increases with increasing rotational speed of the drive shaft.

[0010] On the other hand, a drive shaft assembly for a compressor includes: a drive shaft; a thrust disc coupled to the drive shaft; and an impeller coupled to the thrust disc. The thrust disc includes an outer disk and a hub, the hub including an outer surface. The impeller includes an impeller bore having an inner surface. The hub of the thrust disc is disposed within the impeller bore, and the outer surface of the hub contacts the inner surface of the impeller bore. A first contact force between the outer surface of the hub and the inner surface of the impeller bore increases with increasing rotational speed of the drive shaft.

[0011] In another aspect, the method of assembling the compressor includes connecting the thrust disc to the drive shaft by inserting the drive shaft into a thrust disc bore of the thrust disc. The method also includes connecting the impeller to the thrust disc by inserting the hub of the thrust disc into an impeller bore of the impeller such that the outer surface of the hub contacts the inner surface of the impeller bore, and a first contact force between the outer surface of the hub and the inner surface of the impeller bore increases with increasing rotational speed of the drive shaft. The method further includes mounting a bearing to the compressor housing such that the bearing rotatably supports the outer disc of the thrust disc.

[0012] Various improvements exist to the features mentioned in the foregoing aspects. Other features may also be incorporated into the foregoing aspects. These improvements and additional features may exist individually or in any combination. For example, the various features discussed below with respect to any embodiment of the illustrated embodiments may be incorporated individually or in any combination into any of the foregoing aspects. Attached Figure Description

[0013] The following figures illustrate various aspects of this disclosure.

[0014] Figure 1 It is a 3D view of the assembled compressor.

[0015] Figure 2 It is a section taken along line 2-2. Figure 1 Cross-sectional view of the compressor.

[0016] Figure 3 yes Figure 2 An enlarged cross-sectional view of a portion of the compressor.

[0017] Figure 4 It is a cross-sectional view of the compressor's drive shaft assembly, including the thrust disc and impeller mounted to the end of the drive shaft.

[0018] Figure 5 Is installed to Figure 4 An enlarged cross-sectional view of the thrust disc and impeller at the end of the drive shaft.

[0019] Figure 6 Is installed to Figure 5 An enlarged cross-sectional view of the thrust disc, thrust bearing, and impeller at the end of the drive shaft.

[0020] Figure 7 yes Figure 4 An exploded view of the drive shaft assembly, which includes the thrust disc, impeller, and drive shaft.

[0021] Throughout the accompanying drawings, corresponding reference numerals denote the respective parts. Detailed Implementation

[0022] Reference Figure 1 The compressor 100, illustrated as a two-stage refrigerant compressor, is generally designated 100. The compressor 100 generally includes a compressor housing 102 forming at least one sealed cavity, within which each stage of refrigerant compression is performed. The compressor 100 includes: a first refrigerant inlet 110 for introducing refrigerant vapor into a first compression stage; a first refrigerant outlet 114; a refrigerant transfer conduit 112 for transferring compressed refrigerant from the first compression stage to a second compression stage; and a second refrigerant inlet 118 for introducing refrigerant vapor into a second compression stage (not shown in the diagram). Figure 1 The refrigerant delivery conduit 112 is operatively connected at opposite ends to a first refrigerant outlet 114 and a second refrigerant inlet 118. The second refrigerant outlet 120 delivers compressed refrigerant from the second compression stage to a cooling system in which the compressor 100 is integrated. The refrigerant delivery conduit 112 may also include a refrigerant discharge port 122 for adding or removing refrigerant at the compressor 100 as needed.

[0023] Reference Figure 2 The compressor housing 102 encloses a first compression stage 124 and a second compression stage 126 at opposite ends of the compressor 100. The first compressor stage 124 includes a first-stage impeller 106 configured to impart kinetic energy to refrigerant gas entering via a first refrigerant inlet 110. The kinetic energy imparted to the refrigerant by the first-stage impeller 106 is converted into increased refrigerant pressure (i.e., compression) as the refrigerant velocity decreases during its transmission to a diffuser formed between the first-stage inlet ring 101 and a portion of the outer compressor housing 102. Similarly, the second compression stage 126 includes a second-stage impeller 116 configured to increase the kinetic energy imparted to the refrigerant entering via a second refrigerant inlet 118 from the first compression stage 124. The kinetic energy imparted to the refrigerant by the second-stage impeller 116 is converted into increased refrigerant pressure (i.e., compression) as the refrigerant velocity decreases during its transmission to a diffuser formed between the second-stage inlet ring 103 and a second portion of the outer compressor housing 102. The compressed refrigerant passes through the second refrigerant outlet 120 (not in Figure 2(As shown in the image) Leaving the second compression stage 126.

[0024] The first-stage impeller 106 and the second-stage impeller 116 are about the drive shaft axis A. 104 The rotating drive shaft 104 is connected at opposite ends. The drive shaft extends from the first end 130 to the second end 132 and is about the drive shaft axis A. 104 It is axially symmetric. Furthermore, the drive shaft axis A... 104 The drive shaft 104 extends through its center of gravity. The drive shaft 104 is operatively connected to a motor 108 positioned between the first-stage impeller 106 and the second-stage impeller 116, such that the motor 108 causes the drive shaft 104 to rotate about the drive shaft axis A. 104 Rotation. Both the first-stage impeller 106 and the second-stage impeller 116 are connected to the drive shaft 104, causing the first-stage impeller 106 and the second-stage impeller 116 to rotate at a selected rotational speed to compress the refrigerant to a pre-selected pressure exiting the second refrigerant outlet 120. Any suitable motor can be incorporated into the compressor 100, including but not limited to an electric motor.

[0025] Reference Figures 2 to 4 The drive shaft 104 includes a first shaft portion 134 and a second shaft portion 136, the first shaft portion 134 having a first shaft portion radius R. 134 The second shaft portion 136 has a radius R smaller than that of the first shaft portion. 134 The second axis portion radius R 136 The diameter is reduced, meaning the drive shaft 104 includes a descending feature near the first end 130 of the drive shaft and near the first stage impeller 106. The first shaft portion 134 includes a first end surface 138, and the second shaft portion 136 includes a second end surface 140 disposed on the first end 130 of the drive shaft, away from the first end surface 138. The second shaft portion 136 includes a portion along the drive shaft axis A between the first end surface 138 and the second end surface 140. 104 The length L of the extended second axis section 136 The drive shaft 104 also includes a blind hole 142 along the drive shaft axis A. 104 Extending axially inward from the second end surface 140 to the hole length L in the drive shaft 104 142 That is, blind hole 142 is aligned with the drive shaft axis A. 104 Coaxial. In some exemplary embodiments, the hole length L 142 The length L of the second axis section can be used. 136 Largely the same. Hole 142 includes radius R. 142 The radius R 142 From drive shaft axis A 104The inner surface 144 of the hole extends to define the boundary of the blind hole 142. Hole radius R 142 The radius R of the second axis portion is smaller than 134 Such that the second shaft portion 136 includes a thickness T extending between the inner surface 144 of the hole and the outer surface 146 of the second shaft portion. 136 The annular wall. The hole 142 also includes a tapered end 148 ( Figure 4 ) and the threaded portion defined on the inner surface 144 of the hole.

[0026] Reference Figures 2 to 3 The thrust bearing assembly 200 supports the axial force (e.g., thrust generated by the first-stage impeller 106 and / or the second-stage impeller 116) imparted to the drive shaft 104 during compressor operation. The axial force is generally perpendicular to the drive shaft axis A. 104 Parallel orientation. The thrust bearing assembly 200 may include any suitable bearing type, including, but not limited to, roller bearings, fluid film bearings, pneumatic bearings, and combinations thereof. The thrust bearing assembly 200 includes a bearing support 202 coupled to the compressor housing 102. The bearing support 202 includes a first plate 202a and a second plate 202b spaced apart and disposed on opposite axial sides of the thrust disc 204 of the thrust bearing assembly 200. The first plate 202a and the second plate 202b are annular in shape and include a central opening (not marked) to receive at least a portion of the drive shaft 104 when the compressor 100 is assembled (e.g., ...). Figure 3 (As shown in the diagram). The first plate 202a and the second plate 202b can be coupled to the compressor housing 102 by using any suitable means, including, for example, but not limited to, press-fit connectors and / or mechanical fasteners. Each of the first plate 202a and the second plate 202b may include an inner surface facing the opposite first plate 202a or second plate 202b to support and engage a bearing of the thrust bearing assembly 200.

[0027] Reference Figures 4 to 6 The thrust disk 204 includes a central hub 216 and an outer disk 210 extending radially outward from the hub 216. The thrust disk 204, particularly the hub 216 in the illustrated embodiment, defines a thrust disk bore 206 and includes a thrust disk bore surface 208 defining the boundary of the thrust disk bore 206. Thrust disk axis A 204 The center of gravity extends through the thrust disk 204, and the thrust disk 204 is about the thrust disk axis A. 204 Axisymmetric. Thrust disk bore 206 has a path from thrust disk axis A. 204 The radius R extends to the surface 208 of the thrust disk bore. 206 The second shaft portion 136 of the drive shaft 104 protrudes or extends through the thrust disk bore 206, causing the thrust disk axis A to... 204 and drive shaft axis A104 coincide.

[0028] The thrust disk 204 is connected to the drive shaft 104 via friction or press-fit. For example, the thrust disk bore surface 208 frictionally engages with the outer surface 146 of the second shaft portion, and the outer disk 210 frictionally engages with the first end surface 138 of the drive shaft 104, such that rotation of the drive shaft 104 imparts rotation to the thrust disk 204. The thrust disk bore surface 208 contacts the outer surface 146 of the second shaft portion with a defined gap or space, or without gap or space. Additionally, the radius R... 206 The dimensions are designed to allow interference between the thrust disk 204 and the drive shaft 104. In an exemplary embodiment, a component, such as the thrust disk 204, is coupled to the drive shaft 104 using a press fit, also known as an interference fit and / or a friction fit. After the two interfering parts are press-fitted together, friction is generated between the mating surfaces of the two parts. Based on the amount of interference between the thrust disk 204 and the drive shaft 104, the thrust disk 204 can be assembled onto the drive shaft 104 using a hammer or a hydraulic cylinder. In some cases, the components can be assembled using a shrink-fit technique. The shrink-fit technique is performed by selectively heating and / or cooling the components to be coupled by the shrink-fit. In some embodiments, for example, the thrust disk 204 is heated, causing the thrust disk bore 206 to expand, allowing the second shaft portion 136 to be inserted and positioned within the expanded thrust disk bore 206. Subsequently, the thrust disk bore 206 contracts and shrinks around the second shaft portion 136 as the thrust disk 204 cools. In some implementations, one or more alignment features or components may be used to assemble mating components, including, for example, but not limited to, alignment pins, key engagement features, or other features engaging between the thrust disc and the drive shaft.

[0029] The drive shaft 104, the first-stage impeller 106, and the thrust disk 204 are part of the drive shaft assembly 201 of the compressor 100. In the illustrated embodiment, the drive shaft assembly 201 also includes a second-stage impeller 116. In other embodiments, the drive shaft assembly 201 may include additional or fewer components. In some embodiments, for example, the second-stage impeller 116 may be coupled to the second end 132 of the drive shaft 104 via the thrust disk in the same manner as the first-stage impeller 106.

[0030] Refer again Figure 5 The outer disk 210 includes a first disk surface 212 and an opposite second disk surface 214, the second disk surface 214 being axially spaced from the first disk surface 212 by an opening length L. 210 Hub 216 with hub length L 216 The thrust disk 204 extends axially from the second disk surface 214 to the hub end surface 218. The total length of the thrust disk 204 includes the disk length L. 210 Hub length L216 In some implementations, the hub length L 216 Greater than disk length L 210 The outer disk 210 has a thrust disk axis A 204 The disk radius R measured from the outer circumferential surface 219 of the outer disk 210 210 Hub 216 has a thrust disk axis A 204 The hub radius R is measured to the radial outer surface 220 of hub 216. 216 The outer disk 210 and hub 216 are integrally formed—that is, as a single component, such as by casting or additive manufacturing. In other embodiments, the outer disk 210 and hub 216 may be formed separately and joined together by any suitable means, such as welding.

[0031] Hub radius R 216 Smaller than disk radius R 210 In the illustrated embodiment, for example, the disk radius R 210 Specific hub radius R 216 Approximately 2 to 3 times larger. In another embodiment, the disk radius R 210 It can be compared to the hub radius R 216 It is greater than or less than 2 to 3 times larger. Furthermore, the mass of the outer disk 210 is greater than the mass of the hub 216. Centrifugal force is proportional to mass and its radial distribution. Therefore, during high-speed rotation of the drive shaft 104, the centrifugal force generated on the outer disk 210 is greater than the centrifugal force generated on the hub 216. In some embodiments, the centrifugal force on the outer disk 210 is significantly greater than the centrifugal force on the hub 216.

[0032] The radius R of the thrust disc bore 206 206 The first radius R is less than the first axis portion 134. 134 ( Figure 2 At least a portion of the surface 212 of the first disk contacts the first end surface 138 of the first shaft portion 134. Additionally, the outer disk radius R... 210 The radius R of the portion larger than the first axis 134 This causes a portion of the outer disk 210 to extend radially outward from the first shaft portion 134. The thrust disk 204 is shaped such that the thrust disk 204 is oriented around the thrust disk axis A. 204The cross-section of the plane creates a generally "L-shaped" profile arranged on each side of the second shaft portion 136. The outer disk 210 extends away from the drive shaft 104 such that at least a portion of the outer disk 210 is positioned between the first plate 202a and the second plate 202b of the bearing support 202. The first disk surface 212 is configured to face (i.e., oriented) towards the first plate 202a, and the second disk surface 214 is configured to face (i.e., oriented) towards the second plate 202b. Suitable bearings are supported by the first plate 202a and the second plate 202b and rotatably engaged with the outer disk 210, allowing the outer disk 210 to rotate relative to the first plate 202a and the second plate 202b.

[0033] Reference Figures 5 to 7 The first-stage impeller 106 is along the impeller axis A 106 The length L between the first end 302 and the second end 304 of the impeller extends 106 Impeller shaft A 106 The axis extends through the center of gravity of impeller 106. Impeller 106 is axisymmetric, that is, about the impeller axis A. 106 Symmetrical. The impeller 106 also includes a first impeller bore 306 and a second impeller bore 308, the first impeller bore 306 extending axially from the first end 302 of the impeller into the impeller 106, and the second impeller bore 308 extending axially from the second end 304 of the impeller into the impeller 106. The first impeller bore 306 has a radius R. 306 Furthermore, the second impeller hole 308 has a radius R 308 Radius R 306 Greater than R 308 The first impeller bore 306 and the second impeller bore 308 are arranged such that they together form an opening that extends completely through the impeller 106 from the second end 304 to the first end 302. The impeller 106 also includes a plurality of blades and may include a shroud. The impeller 106 may include any suitable type of blades for imparting kinetic energy to the incoming refrigerant.

[0034] The first impeller bore 306 includes an inner impeller surface 310 that defines the boundary of the first impeller bore 306. The hub 216 of the thrust disk 204 is disposed within the first impeller bore 306 of the impeller 106, such that the impeller axis A... 106 With thrust disk axis A 204 and drive shaft axis A 104The two overlap. The hub 216 press-fits within the first impeller bore 306, such that the outer surface 220 is frictionally connected to the inner surface 310 of the impeller with minimal clearance or space. In some exemplary embodiments, the hub 216 may be frictionally connected to the first impeller bore 306 using a shrink-fit technique. Therefore, rotation of the drive shaft 104 causes rotation of the thrust disk 204 and the impeller 106. The thrust disk 204 transmits torque from the drive shaft 104 to the impeller 106, and therefore, the impeller 106 is not directly mounted to the drive shaft 104. The thrust disk 204 and the impeller 106 are arranged relative to the drive shaft 104 such that the centers of gravity of both the thrust disk 204 and the impeller 106 are aligned with the drive shaft axis A. 104 Alignment. In other words, drive shaft axis A. 104 Thrust disk axis A 204 and impeller shaft A 106 All are coaxial. Furthermore, the components of drive shaft 104, thrust disk 204, and impeller 106 are arranged around drive shaft axis A. 104 Axisymmetric.

[0035] Refer again Figure 6 In some exemplary embodiments, hub 216 includes a first hub portion 216a and a second hub portion 216b, the first hub portion 216a extending from outer disk 210 and the second hub portion 216b extending from first hub portion 216a. The first hub portion 216a includes a first outer surface 220a and a first inner surface 208a, the first inner surface 208a defining a first portion 206a of thrust disk bore 206. The first hub portion 216a has a thrust disk axis A... 204 The inner hub radius (not shown) measured to the first inner surface 208a and from the thrust disk axis A 204 The outer radius (not shown) is measured to the first outer surface 220a. The second hub portion 216b includes a second outer surface 220b and a second inner surface 208b, the second inner surface 208b defining a second portion 206b of the thrust disk bore 206. The second hub portion 216b includes a portion extending from the thrust disk axis A. 204 The inner hub radius (not shown) measured to the second inner surface 208b and from the thrust disk A 204The outer radius (not shown) is measured to the second outer surface 220b. The outer radius of the second hub portion 216b is smaller than that of the first hub portion 216a, resulting in greater interference (i.e., a tighter fit) between the first outer surface 220a and the impeller inner surface 310 compared to the interference between the second outer surface 220b and the impeller inner surface 310. In some embodiments, a gap or clearance C2 may exist between the second outer surface 220b and the impeller inner surface 310. For example, the gap C2 may be between 0.1 mm and 1 mm. The second outer surface 220b of the second hub portion 216b may include threads that can facilitate removal of the thrust disc 204 from the drive shaft 104 during disassembly.

[0036] The inner radius of the second hub portion 216b can be smaller than the inner radius of the first hub portion 216a, such that the second inner surface 208b has greater interference (i.e., a tighter fit) with the drive shaft 104 compared to the interference between the first inner surface 208a and the drive shaft 104. In some embodiments, a gap or clearance C1 may exist between the first inner surface 208a and the drive shaft 104. For example, the gap C1 between the first inner surface 208a and the drive shaft 104 can be between 0.1 (mm) and 1 (mm).

[0037] The rotation of drive shaft 104, thrust disk 204 and impeller 106 causes rotation along axis A perpendicular to drive shaft. 104 The centrifugal force is directed radially outward. The resulting centrifugal force increases with the square of the rotational speed. The centrifugal force is related to the mass about the axis of rotation, i.e., the axis A of the drive shaft. 104 The radially distributed inertial force is proportional. The outer disk 210 has a hub radius R that is proportional to that of the hub 216. 216 Compared to a larger radius R 210 Therefore, the outer disk 210 experiences a greater centrifugal force than the hub 216. The centrifugal force on the outer disk 210 is along a direction perpendicular to the drive shaft axis A. 104 The centrifugal force on the outer disk 210 pulls it away from the drive shaft 104 in the radial direction. The centrifugal force on the outer disk 210 also exerts an outward radial force on the first hub portion 216a near the outer disk 210. This outward radial force on the first hub portion 216a causes the first outer surface 220a of the first hub portion 216a to press against the inner surface 310 of the impeller, forming a force called the first contact force F1, thereby increasing the frictional connection between the first outer surface 220a and the inner surface 310 of the impeller. The first contact force F1 increases with the rotational speed of the drive shaft 104 and provides sufficient contact force to maintain the frictional connection between the hub 216 and the impeller 106, and to keep the center of gravity of the impeller 106 aligned with the center of gravity of the thrust disk 204 at high rotational speeds.

[0038] Centrifugal force on the second hub portion 216b pulls it radially outward away from the drive shaft 104. Centrifugal force on the outer disk 210 and the first hub portion 216a can cause the second hub portion 216b to slightly flex radially inward toward the drive shaft 104. In some embodiments, the frictional engagement between the second hub portion 216b and the drive shaft 104 can decrease as the rotational speed of the drive shaft 104 increases. The contact force F2 between the second inner surface 208b of the second hub portion 216b and the drive shaft 104 is sufficient to maintain the frictional connection between the thrust disk 204 and the drive shaft 104, and to maintain the center of gravity of the thrust disk 204 aligned with the drive shaft axis A at the normal operating speed of the drive shaft 104. 104 Alignment. In other words, as the rotational speed of the drive shaft 104 increases, the interference fit or connection between the thrust disk 204 and the drive shaft 104 can be slightly reduced, and the connection between the thrust disk 204 and the impeller 106 becomes stronger (i.e., tighter). The friction fit or connection between the thrust disk 204 and the drive shaft 104 prevents slippage or relative movement between the thrust disk 204 and the drive shaft 104, and allows torque to be transmitted from the drive shaft 104 to the thrust disk 204 and, therefore, from the drive shaft 104 to the impeller 106.

[0039] The impeller 106 also includes a screw 314 extending through the second impeller bore 308 and the first impeller bore 306, and entering a blind bore 142 in the drive shaft 104. The screw 314 includes a threaded portion having threads that engage with threads defined on an inner surface 144 (not shown) of the bore. The screw 314 includes a head 316 that engages with the second end 304 of the impeller. When the screw 314 is tightened, it compresses the impeller 106 against the thrust disc 204, thereby facilitating the transmission of torque from the thrust disc 204 to the impeller 106. More specifically, the screw 314 forces the first end 302 of the impeller into contact with the second disc surface 214 of the thrust disc 204, thereby compressing a portion of the outer disc 210 between the first end 302 of the impeller and the first end surface 138 of the drive shaft 104. The tightening of the screw 314 creates a clamping force on the thrust disc 204. The threads of screw 314 are arranged such that rotation of drive shaft 104 will not cause the threads of screw 314 to loosen or unscrew from the threads of blind hole 142.

[0040] Therefore, in the illustrated embodiment of this disclosure, the thrust disk 204, impeller 106, and drive shaft 104 are arranged such that the frictional connection or fit between the components is maintained at the operating rotational speed of the drive shaft 104. The frictional fit between the drive shaft 104 and the thrust disk 204 may decrease slightly as the rotational speed of the drive shaft 104 increases. The decrease in the frictional fit between the drive shaft 104 and the thrust disk 204 is not highly dependent on the rotational speed of the drive shaft 104. Furthermore, an increase in the rotational speed of the drive shaft 104 can increase the frictional connection between the thrust disk 204 and the impeller 106. More specifically, an increase in the rotational speed of the drive shaft 104 increases the first contact force F1 between the hub 216 and the impeller 106 and only slightly decreases the second contact force F2 between the hub 216 and the drive shaft 104. The first contact force F1 and the second contact force F2 are sufficient to maintain the frictional connection between the assembled components. In addition, the assembly of the components ensures that the center of gravity of the thrust disk 204 and the center of gravity of the impeller 106 coincide with the axis of rotation, thereby limiting the centrifugal load at high rotational speeds.

[0041] The described system and method achieve better results compared to existing systems and methods associated with thrust bearing assemblies. The thrust disc, impeller, and drive shaft assembly helps maintain alignment of rotating components at high rotational operating speeds consistent with the compressor system. The high rotational operating speed of the drive shaft increases the frictional fit connection between the thrust disc and the impeller, and maintains the frictional fit connection between the thrust disc and the drive shaft. In some embodiments, the impeller is not directly coupled to the drive shaft, and torque is transmitted from the drive shaft to the impeller via the thrust disc. The improved frictional fit connection maintains alignment between the center of gravity of the thrust disc, the center of gravity of the impeller, and the center of gravity of the drive shaft with the axis of rotation. The disclosed assembly is compatible with centrifugal compressors that typically operate at high rotational speeds. The assembly of the components described herein can be incorporated into the design of any type of centrifugal compressor. Non-limiting examples of centrifugal compressors suitable for the disclosed system include single-stage, two-stage, and multi-stage centrifugal compressors. Furthermore, the described assembly is well-suited for other applications including other mechanical systems with components such as impellers and bearing assemblies coupled to high-speed drive shafts.

[0042] Unlike known bearing systems and impellers mounted on the drive shaft of a compressor system, the thrust disc, impeller, and drive shaft assembly described in this disclosure allows for alignment of the component centers of gravity and maintains a friction-fit connection, regardless of the high rotational speed of the drive shaft—both crucial factors for the successful implementation of the centrifugal compressor as described above. Furthermore, the high rotational speed improves the frictional fit between the thrust disc and impeller, thereby maintaining the frictional connection and preventing centrifugal loads on the drive shaft. The described assembly can result in improved service life while reducing component wear, thus lowering costs associated with maintenance and downtime of rotating machinery. The described assembly provides enhanced features that increase service life and durability of the impeller, thrust disc, and drive shaft used in the challenging operating environments of refrigerant compressors in HVAC systems.

[0043] The foregoing has described in detail exemplary embodiments of compressor systems and methods, such as refrigerant compressors. The systems and methods are not limited to the specific embodiments described herein; rather, components of the system and methods can be used independently and separately from other components described herein. For example, the impeller and thrust disk described herein can be used in compressors other than refrigerant compressors, such as turbocharger compressors.

[0044] When elements are introduced in this disclosure or in embodiments thereof, the articles “a,” “an,” “the,” and “the” are intended to indicate the presence of one or more of the elements. The terms “comprising,” “including,” “containing,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to the listed elements. The use of terms indicating a particular orientation (e.g., “top,” “bottom,” “side,” etc.) is for ease of description and does not require any particular orientation of the object being described.

[0045] Since various changes can be made to the above structures and methods without departing from the scope of this disclosure, it is intended that all content contained in the above description and shown in the accompanying drawings should be interpreted as illustrative rather than restrictive.

Claims

1. A compressor system, comprising: Compressor housing; A drive shaft, which is rotatably supported within the compressor housing; An impeller that imparts kinetic energy to incoming refrigerant gas when the drive shaft rotates, wherein the impeller includes an impeller bore having an inner surface; A thrust disk, coupled to the drive shaft, includes an outer disk and a hub, the hub being disposed within the impeller bore, wherein the hub includes an outer surface contacting the inner surface of the impeller bore, and wherein the thrust disk defines a thrust disk bore having an inner surface contacting the drive shaft, and wherein a first contact force between the outer surface of the hub and the inner surface of the impeller bore increases with increasing rotational speed of the drive shaft, and wherein the inner surface of the bore flexes radially inward toward the drive shaft with increasing rotational speed of the drive shaft, thereby generating a second contact force between the inner surface of the bore and the drive shaft; and A bearing assembly, mounted to the compressor housing, rotatably supporting the outer disk of the thrust disk. The inner surface of the hole includes a first inner surface and a second inner surface. The first inner surface is close to the outer disk, and the second inner surface is away from the outer disk. The second contact force is between the second inner surface and the drive shaft. The outer surface of the hub includes a first portion and a second portion, the first portion being close to the outer disk and the second portion being away from the outer disk, wherein the first contact force is between the first portion of the outer surface of the hub and the inner surface of the impeller hole.

2. The compressor system according to claim 1, wherein, The drive shaft is press-fitted into the thrust disc bore.

3. The compressor system according to claim 2, wherein, The frictional connection between the inner surface of the hole and the drive shaft is maintained during the operating rotational speed of the drive shaft.

4. The compressor system according to claim 1, wherein, The drive shaft includes an inner blind hole, which includes a threaded portion.

5. The compressor system according to claim 4, comprising a screw disposed within the impeller bore and the inner blind bore of the drive shaft, wherein, The screw includes a screw thread portion that is threadedly engaged with the threaded portion of the hole.

6. The compressor system according to claim 5, wherein, The rotation of the drive shaft does not cause the screw, which is threadedly engaged with the threaded portion of the hole, to disengage.

7. The compressor system according to claim 1, wherein, The outer disk includes an outer disk radius and an outer disk moment of inertia, and the hub includes a hub radius and a hub moment of inertia, wherein the outer disk radius and the outer disk moment of inertia are greater than the hub radius and the hub moment of inertia.

8. The compressor system according to claim 1, wherein, The impeller is not directly connected to the drive shaft.

9. A drive shaft assembly for a compressor, the drive shaft assembly comprising: Drive shaft; A thrust disc, coupled to the drive shaft and including an outer disc and a hub, wherein the hub includes an outer surface, and wherein the thrust disc defines a thrust disc bore having an inner surface that contacts the drive shaft; and An impeller connected to the thrust disk, the impeller including an impeller bore having an inner surface; The hub of the thrust disk is disposed within the impeller bore, and the outer surface of the hub contacts the inner surface of the impeller bore. A first contact force between the outer surface of the hub and the inner surface of the impeller bore increases with the rotational speed of the drive shaft. The inner surface of the bore flexes radially inward toward the drive shaft with increasing rotational speed, thereby generating a second contact force between the inner surface of the bore and the drive shaft. The inner surface of the hole includes a first inner surface and a second inner surface. The first inner surface is close to the outer disk, and the second inner surface is away from the outer disk. The second contact force is between the second inner surface and the drive shaft. The outer surface of the hub includes a first portion and a second portion, the first portion being close to the outer disk and the second portion being away from the outer disk, wherein the first contact force is between the first portion of the outer surface of the hub and the inner surface of the impeller hole.

10. The drive shaft assembly according to claim 9, wherein, The drive shaft is press-fitted into the thrust disc bore.

11. The drive shaft assembly of claim 10, wherein, The frictional connection between the inner surface of the hole and the drive shaft is maintained during the operating rotational speed of the drive shaft.

12. The drive shaft assembly according to claim 9, wherein, The drive shaft includes an inner blind hole, which includes a threaded portion.

13. The drive shaft assembly of claim 12, comprising a screw disposed within the impeller bore and the inner blind bore of the drive shaft, wherein, The screw includes a screw thread portion that is threadedly engaged with the threaded portion of the hole.

14. The drive shaft assembly according to claim 9, wherein, The outer disk includes an outer disk radius and an outer disk moment of inertia, and the hub includes a hub radius and a hub moment of inertia, wherein the outer disk radius and the outer disk moment of inertia are greater than the hub radius and the hub moment of inertia.

15. The drive shaft assembly according to claim 9, wherein, The impeller is not directly connected to the drive shaft.

16. A method for assembling a compressor, the method comprising: The thrust disk is connected to the drive shaft by inserting the drive shaft into the thrust disk bore, the thrust disk bore having an inner surface such that the inner surface of the bore contacts the drive shaft; The impeller is connected to the thrust disk by inserting the hub of the thrust disk into the impeller bore of the impeller, such that the outer surface of the hub contacts the inner surface of the impeller bore. A first contact force between the outer surface of the hub and the inner surface of the impeller bore increases with the rotational speed of the drive shaft. Furthermore, the inner surface of the bore flexes radially inward toward the drive shaft with increasing rotational speed, thereby generating a second contact force between the inner surface of the bore and the drive shaft. The bearing is installed into the compressor housing such that it rotatably supports the outer disk of the thrust disc. The inner surface of the hole includes a first inner surface and a second inner surface. The first inner surface is close to the outer disk, and the second inner surface is away from the outer disk. The second contact force is between the second inner surface and the drive shaft. The outer surface of the hub includes a first portion and a second portion, the first portion being close to the outer disk and the second portion being away from the outer disk, wherein the first contact force is between the first portion of the outer surface of the hub and the inner surface of the impeller hole.

Images