WO2021155278A1

WO2021155278A1 - Compressor bearing

Info

Publication number: WO2021155278A1
Application number: PCT/US2021/015892
Authority: WO
Inventors: James A. Schaefer; Jason P. Lochner; William E. MCKINNEY
Original assignee: Emerson Climate Technologies, Inc.
Priority date: 2020-01-31
Filing date: 2021-01-29
Publication date: 2021-08-05
Also published as: US20210239113A1

Abstract

A compressor may include a shell assembly, a first scroll, a second scroll, a driveshaft, and a bearing. The first scroll includes a first end plate and a first spiral wrap extending from the first end plate. The second scroll includes a second end plate and a second spiral wrap extending from the second end plate. The spiral wraps engage each other to form fluid pockets. The driveshaft may engage one of the scrolls. The bearing supports the driveshaft for rotation relative to the shell assembly. The bearing includes first and second axial ends and an aperture extending through the first and second axial ends. The driveshaft extends through the aperture. The aperture is defined by an inner diametrical surface of the bearing. The inner diametrical surface may include a tapered portion that extends radially outward as the tapered portion extends axially toward the first axial end of the bearing.

Description

COMPRESSOR BEARING

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Utility Patent Application No. 16/779,020, filed on January 31 , 2020. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to a compressor, and more particularly, to a compressor bearing.

BACKGROUND [0003] This section provides background information related to the present disclosure and is not necessarily prior art.

[0004] Heat-pump systems, air-conditioning systems, and other working-fluid- circulation systems may include a fluid circuit having an outdoor heat exchanger, an indoor heat exchanger, an expansion device disposed between the indoor and outdoor heat exchangers, and a compressor circulating a working fluid (e.g., refrigerant or carbon dioxide) between the indoor and outdoor heat exchangers. Efficient and reliable operation of the compressor is desirable to ensure that the heat-pump system in which the compressor is installed is capable of effectively and efficiently providing a cooling and/or heating effect on demand.

SUMMARY

[0005] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0006] The present disclosure provides a compressor that may include a shell assembly, a first scroll, a second scroll, a driveshaft, and a bearing. The first scroll may be disposed within the shell assembly and may include a first end plate and a first spiral wrap extending from the first end plate. The second scroll may include a second end plate and a second spiral wrap extending from the second end plate. The first and second spiral wraps meshing engage each other to form moving fluid pockets therebetween. The driveshaft may drivingly engage one of the first and second scrolls. The bearing may support the driveshaft for rotation relative to the shell assembly. The bearing includes a first axial end, a second axial end, and an aperture extending through the first and second axial ends. The driveshaft extends through the aperture. The aperture is defined by an inner diametrical surface of the bearing. The inner diametrical surface may include a tapered portion that extends radially outward as the tapered portion extends axially toward the first axial end of the bearing.

[0007] In some configurations of the compressor of the above paragraph, the first axial end of the bearing is disposed axially between the second scroll and the second axial end of the bearing.

[0008] In some configurations of the compressor of either of the above paragraphs, the inner diametrical surface includes a straight portion disposed axially between the tapered portion and the second axial end of the bearing. The tapered portion is angled relative to the straight portion.

[0009] In some configurations of the compressor of any one or more of the above paragraphs, the bearing is a bi-metal bearing.

[0010] In some configurations of the compressor of any one or more of the above paragraphs, the bearing includes an aluminum cladding.

[0011] In some configurations of the compressor of any one or more of the above paragraphs, the driveshaft includes a concentric portion and an eccentric crank pin extending from an axial end of the concentric portion.

[0012] In some configurations of the compressor of any one or more of the above paragraphs, the bearing supports the concentric portion, and wherein the eccentric crank pin is disposed axially between the bearing and the second end plate.

[0013] In some configurations, the compressor of any one or more of the above paragraphs includes another bearing supporting the concentric portion of the driveshaft.

[0014] In some configurations, the compressor of any of the above paragraphs includes a motor assembly disposed within the shell assembly and drivingly engaging the driveshaft.

[0015] In some configurations, the compressor of any one or more of the above paragraphs includes a bearing housing fixed to the shell assembly, wherein the bearing is disposed within the bearing housing.

[0016] In another form, the present disclosure provides a compressor that may include a first scroll, a second scroll, a driveshaft, and a bearing housing assembly. The first scroll may include a first end plate and a first spiral wrap extending from the first end plate. The second scroll may include a second end plate and a second spiral wrap extending from the second end plate. The first and second spiral wraps may meshing engage each other to form moving fluid pockets therebetween. The driveshaft may drivingly engaging the second scroll. The bearing housing assembly may support the driveshaft for rotation. The bearing housing assembly may include a fixed bearing housing and a bearing disposed within the bearing housing. The bearing housing may support the second scroll. The bearing includes a first axial end, a second axial end, and an aperture extending through the first and second axial ends. The driveshaft extends through the aperture. The aperture is defined by an inner diametrical surface of the bearing. The inner diametrical surface may include a tapered portion that extends radially outward as the tapered portion extends axially toward the first axial end of the bearing.

[0017] In some configurations of the compressor of the above paragraph, the first axial end of the bearing is disposed axially between the second scroll and the second axial end of the bearing.

[0018] In some configurations of the compressor of either of the above paragraphs, the inner diametrical surface includes a straight portion disposed axially between the tapered portion and the second axial end of the bearing, wherein the tapered portion is angled relative to the straight portion.

[0019] In some configurations of the compressor of any one or more of the above paragraphs, the driveshaft includes a concentric portion and an eccentric crank pin extending from an axial end of the concentric portion.

[0020] In some configurations of the compressor of any one or more of the above paragraphs, the bearing supports the concentric portion. The eccentric crank pin may be disposed axially between the bearing and the second end plate.

[0021] In some configurations, the compressor of any one or more of the above paragraphs includes another bearing supporting the concentric portion of the driveshaft.

[0022] In some configurations of the compressor of any one or more of the above paragraphs, the bearing is a bi-metal bearing.

[0023] In some configurations of the compressor of any one or more of the above paragraphs, the bearing includes an aluminum cladding.

[0024] In some configurations, the compressor of any one or more of the above paragraphs includes a motor assembly drivingly engaging the driveshaft. [0025] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0026] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0027] Figure 1 is a cross-sectional view of a compressor according to the principles of the present disclosure;

[0028] Figure 2 is a schematic cross-sectional view of a driveshaft and first and second bearings of the compressor of Figure 1 ; and

[0029] Figure 3 is a schematic cross-sectional view of the first bearing.

[0030] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0031] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0032] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0033] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0034] When an element or layer is referred to as being "on," “engaged to,” "connected to," or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," “directly engaged to,” "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[0035] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0036] Spatially relative terms, such as “inner,” “outer,” "beneath," "below," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0037] With reference to Figure 1 , a compressor 26 is provided that may include a hermetic shell assembly 36, a first bearing housing assembly 38, a second bearing housing assembly 39, a motor assembly 40, a driveshaft 41 , a compression mechanism 42, and a seal assembly 44. The compressor 26 may compress a working fluid (e.g., a refrigerant) and circulate the working fluid throughout a vapor-compression system, for example.

[0038] The shell assembly 36 may form a compressor housing and may include a cylindrical shell 54, an end cap 56 at an upper end thereof, a transversely extending partition 58, and a base 60 at a lower end thereof. The end cap 56 and the partition 58 may define a discharge chamber 62. The partition 58 may separate the discharge chamber 62 from a suction chamber 63. The partition 58 may include a wear ring 64 and a discharge passage 65 extending therethrough to provide communication between the compression mechanism 42 and the discharge chamber 62. A discharge fitting 46 may be attached to shell assembly 36 at an opening 66 in the end cap 56. The discharge valve assembly 48 can be disposed within the discharge fitting 46 and may generally prevent a reverse flow condition. A suction inlet fitting 50 may be attached to shell assembly 36 at an opening 68.

[0039] The first bearing housing assembly 38 may be fixed relative to the shell 54 and may include a main bearing housing 70, a first bearing 72, sleeves guides or bushings 74, and fasteners 76. The main bearing housing 70 may house the first bearing 72 therein and may define an annular flat thrust bearing surface 78 on an axial end surface thereof. The main bearing housing 70 may include apertures 80 extending therethrough and receiving the fastener assemblies 76. The second bearing housing assembly 39 may be fixed relative to the shell 54 and may include a lower bearing housing 71 , a second bearing 73.

[0040] The motor assembly 40 may include a motor stator 82 and a rotor 84. The motor stator 82 may be press fit into the shell 54. The rotor 84 may be press fit on the driveshaft 41 and may transmit rotational power to the driveshaft 41 . The driveshaft 41 may be rotatably supported within the first and second bearing housing assemblies 38, 39. The driveshaft 41 may include a concentric portion 87 and an eccentric crank pin 88 having a flat 90 thereon. The first and second bearings 72, 73 may support (i.e., contact) the concentric portion 87 of the driveshaft 41 for rotation relative to the shell assembly 36. In the configuration shown in Figure 1 , the rotor 84 is disposed between the first and second bearings 72, 73 in an axial direction (i.e., a direction along a rotational axis of the driveshaft 41).

[0041] The compression mechanism 42 may include an orbiting scroll 92 and a non-orbiting scroll 94. The orbiting scroll 92 may include an end plate 96 having a spiral wrap 98 on an upper surface thereof and an annular flat thrust surface 100 on a lower surface. The thrust surface 100 may interface with the annular flat thrust bearing surface 78 on the main bearing housing 70. A cylindrical hub 102 may project downwardly from thrust surface 100 and may include a drive bushing 104 disposed therein. The drive bushing 104 may include an inner bore 105 in which the crank pin 88 is drivingly disposed. The crank pin flat 90 may drivingly engage a flat surface in a portion of the inner bore 105 to provide a radially compliant driving arrangement. An Oldham coupling 106 may be engaged with the orbiting and non-orbiting scrolls 92, 94 to prevent relative rotation therebetween.

[0042] The non-orbiting scroll 94 may include an end plate 108 and a spiral wrap 110 projecting downwardly from the end plate 108. The spiral wrap 110 may meshingly engage the spiral wrap 98 of the orbiting scroll 92, thereby creating a series of moving fluid pockets. The fluid pockets defined by the spiral wraps 98, 110 may decrease in volume as they move from a radially outer position (at a suction pressure) to a radially intermediate position (at an intermediate pressure) to a radially inner position (at a discharge pressure) throughout a compression cycle of the compression mechanism 42.

[0043] The end plate 108 may include a discharge passage 112, a discharge recess 114, an intermediate passage 116, and an annular recess 118. The discharge passage 112 is in communication with one of the fluid pockets at the radially inner position and allows compressed working fluid (at the discharge pressure) to flow through the discharge recess 114 and into the discharge chamber 62. The intermediate passage 116 may provide communication between one of the fluid pockets at the radially intermediate position and the annular recess 118. The annular recess 118 may encircle the discharge recess 114 and may be substantially concentric therewith. The annular recess 118 may include an inner surface 119 and an outer surface 121. [0044] The annular recess 118 may at least partially receive the seal assembly 44 and may cooperate with the seal assembly 44 to define an axial biasing chamber 120 therebetween. The biasing chamber 120 receives fluid from the fluid pocket in the intermediate position through the intermediate passage 116. A pressure differential between the intermediate-pressure fluid in the biasing chamber 120 and fluid in the suction chamber 63 exerts a net axial biasing force on the non-orbiting scroll 94 urging the non-orbiting scroll 94 toward the orbiting scroll 92. In this manner, the tips of the spiral wrap 110 of the non-orbiting scroll 94 are urged into sealing engagement with the end plate 96 of the orbiting scroll 92 and the end plate 108 of the non-orbiting scroll 94 is urged into sealing engagement with the tips of the spiral wrap 98 of the orbiting scroll 92.

[0045] Referring now to Figures 2 and 3, the first and second bearings 72, 73 are annular members that support the driveshaft 41 for rotation during operation of the compressor 26. Either or both of the first and second bearings 72, 73 could be bi-metal aluminum bearings (e.g., the first bearing 72 is shown in Figure 3 with a steel substrate 140 with an aluminum cladding 142 or plating). In some embodiments, either or both of the first and second bearings 72, 73 could be formed from any other metal(s), polymer(s), or any combination of metal(s) and polymer(s), etc. The first bearing 72 includes an aperture 130 defining an inner diametrical surface 131 of the first bearing 72. The aperture 130 defines a rotational axis R of the driveshaft 41 and extends through a first axial end 132 and a second axial end 134 of the first bearing 72. The driveshaft 41 extends through the aperture 130.

[0046] The inner diametrical surface 131 of the first bearing 72 may include a generally straight portion 136 and a tapered portion 138. The tapered portion 138 extends radially outward from the straight portion 136 as the tapered portion 138 extends axially toward the first axial end 132 of the first bearing 72. The tapered portion 138 may be oriented at an angle A relative to the straight portion 136. The tapered portion 138 may have a length L (extending in an axial direction) from the first axial end 132 to an axial end of the straight portion 136. The tapered portion 138 can be machined, coined, or otherwise formed into the inner diametrical surface 131. While the tapered portion 138 is shown in Figures 2 and 3 as having a constant slope over the length L, in some embodiments, the tapered portion 138 could have a non-constant slope over the length L (e.g., the tapered portion 138 could have a curved cross section and/or a cross section with multiple segments with differing slopes). [0047] During operation of the compressor 26, the driveshaft 41 may deflect or bend (an exaggerated shaft deflection is shown in Figure 2). Such deflection causes increased edge-loading on prior-art bearings, which can lead to undesirable wear on such bearings (particularly on bearings with an aluminum substrate or cladding). The tapered portion 138 of the first bearing 72 of the present application reduces edge loading and associated wear, and can prolong the usable life of the bearing 72 (especially in embodiments where the bearing 72 is a bi-metal aluminum bearing). In addition to reducing wear, the tapered portion 138 may reduce friction between the bearing 72 and the driveshaft 41 by distributing the load more favorably, which may result in an improved oil film layer on the bearing 72. This reduction in friction and improved oil film layer can improve the efficiency of the compressor 26.

[0048] The angle A and length L of the tapered portion 138 may be selected to substantially match an angle at which the driveshaft 41 deflects during operation of the motor assembly 40 at a selected rotational speed (or range of speeds) and/or under selected load conditions. In addition to motor speed and load, the amount of deflection may depend on the stiffness of the driveshaft 41 . Testing and/or finite-element-analysis can be conducted to determine the amount of driveshaft deflection and the dimensions of the angle A and length L. It should be understood that the angle A shown in Figures 2 and 3 is exaggerated for illustration purposes and is not necessarily drawn to-scale. That is, the angle A may be quite small. In one example, the angle A may be selected such that the tapered portion 138 extends radially outward by about 0.25 millimeters (250 microns) or less over the length L.

[0049] In some configurations, the entire inner diametrical surface 131 could be tapered - i.e., the tapered portion 138 could extend from the first axial end 132 to the second axial end 134 of the first bearing 72. In some configurations, the first bearing 72 could include a second tapered portion (similar to the tapered portion 138) formed adjacent to the second axial end 134 such that the straight portion 136 could be disposed between the tapered portion 138 at the first axial end 132 and the second tapered portion at the second axial end 134. In some configurations, the first bearing 72 could include a tapered portion only at the second axial end 134. In some configurations, the second bearing 73 could include one or more tapered portions (like the tapered portion 138) at either or both axial ends of the second bearing 73. In other configurations, the inner diametrical surface of the second bearing 73 may be entirely straight (like the straight portion 136). [0050] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMS What is claimed is:

1. A compressor comprising: a shell assembly; a first scroll disposed within the shell assembly and including a first end plate and a first spiral wrap extending from the first end plate; a second scroll including a second end plate and a second spiral wrap extending from the second end plate, wherein the first and second spiral wraps meshing engage each other to form moving fluid pockets therebetween; a driveshaft drivingly engaging one of the first and second scrolls; and a bearing supporting the driveshaft for rotation relative to the shell assembly, wherein: the bearing includes a first axial end, a second axial end, and an aperture extending through the first and second axial ends, the driveshaft extends through the aperture, the aperture is defined by an inner diametrical surface of the bearing, and the inner diametrical surface including a tapered portion that extends radially outward as the tapered portion extends axially toward the first axial end of the bearing.

2. The compressor of claim 1 , wherein the first axial end of the bearing is disposed axially between the second scroll and the second axial end of the bearing.

3. The compressor of claim 2, wherein the inner diametrical surface includes a straight portion disposed axially between the tapered portion and the second axial end of the bearing, wherein the tapered portion is angled relative to the straight portion.

4. The compressor of claim 3, wherein the bearing is a bi-metal bearing.

5. The compressor of claim 4, wherein the bearing includes an aluminum cladding.

6. The compressor of claim 1 , wherein the driveshaft includes a concentric portion and an eccentric crank pin extending from an axial end of the concentric portion.

7. The compressor of claim 6, wherein the bearing supports the concentric portion, and wherein the eccentric crank pin is disposed axially between the bearing and the second end plate.

8. The compressor of claim 7, further comprising another bearing supporting the concentric portion of the driveshaft.

9. The compressor of claim 1 , further comprising a motor assembly disposed within the shell assembly and drivingly engaging the driveshaft.

10. The compressor of claim 1 , further comprising a bearing housing fixed to the shell assembly, wherein the bearing is disposed within the bearing housing.

11 . A compressor comprising: a first scroll including a first end plate and a first spiral wrap extending from the first end plate; a second scroll including a second end plate and a second spiral wrap extending from the second end plate, wherein the first and second spiral wraps meshing engage each other to form moving fluid pockets therebetween; a driveshaft drivingly engaging the second scroll; and a bearing housing assembly supporting the driveshaft for rotation, the bearing housing assembly including a fixed bearing housing and a bearing disposed within the bearing housing wherein: the bearing housing supports the second scroll, the bearing includes a first axial end, a second axial end, and an aperture extending through the first and second axial ends, the driveshaft extends through the aperture, the aperture is defined by an inner diametrical surface of the bearing, and the inner diametrical surface including a tapered portion that extends radially outward as the tapered portion extends axially toward the first axial end of the bearing.

12. The compressor of claim 11 , wherein the first axial end of the bearing is disposed axially between the second scroll and the second axial end of the bearing.

13. The compressor of claim 12, wherein the inner diametrical surface includes a straight portion disposed axially between the tapered portion and the second axial end of the bearing, wherein the tapered portion is angled relative to the straight portion.

14. The compressor of claim 13, wherein the driveshaft includes a concentric portion and an eccentric crank pin extending from an axial end of the concentric portion.

15. The compressor of claim 14, wherein the bearing supports the concentric portion, and wherein the eccentric crank pin is disposed axially between the bearing and the second end plate.

16. The compressor of claim 15, further comprising another bearing supporting the concentric portion of the driveshaft.

17. The compressor of claim 16, wherein the bearing is a bi-metal bearing.

18. The compressor of claim 17, wherein the bearing includes an aluminum cladding.

19. The compressor of claim 11 , further comprising a motor assembly drivingly engaging the driveshaft.