Subject matter disclosed herein relates generally to bearing systems for turbomachinery such as turbochargers for internal combustion engines.
Turbomachines rely on turbines to convert fluid energy to mechanical energy. In most configurations, a turbine is connected to a shaft supported by one or more bearings where the shaft rotates along with the turbine as the turbine extracts energy from a fluid stream. For exhaust driven turbines, a shaft may rotate at over 100,000 rpm. Turbomachinery operating at such high rotational speeds generate a significant amount noise.
One type of turbomachinery noise stems lubrication instabilities known as “whirl”. Another type of turbomachinery noise is associated with component clearances and commonly referred to as “rub” (e.g., component-to-component contact). While appropriate choices in lubricant, balancing, and component clearances can minimize noise, no turbomachine operates silently. As described herein, various exemplary arrangements, materials and techniques aim to reduce generation and transmission of turbomachinery noise, especially for turbochargers.
A more complete understanding of the various arrangements, techniques, etc., described herein, and equivalents thereof, may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings wherein:
Turning to the drawings, various methods are illustrated as being optionally implemented in a suitable control and/or computing environment, for example, in the general context of computer-executable instructions, such as program modules, being executed by a computer and/or other computing device (e.g., including robotic devices for use in manufacturing components or assemblies). Generally, program modules include instructions, routines, programs, objects, components, data structures, etc. One or more computer-readable media may be used to store such information. One or more machines may, at least in part, be programmed or otherwise instructed to perform part or all of various methods described herein.
In some diagrams herein, various algorithmic acts are summarized in individual “blocks”. Such blocks describe specific actions or decisions that are made or carried out as a process proceeds. Where a controller (or equivalent) is employed, the flow charts presented herein provide a basis for a “control program” or software/firmware that may be used by such a controller (or equivalent) to control a device and/or a system. As such, various processes may be implemented as machine-readable instructions storable in memory that, when executed by a processor, perform various acts illustrated as blocks. In addition, various diagrams include individual “blocks” that are optionally structural elements of a device and/or a system. For example, a “controller block” optionally includes a controller as a structural element.
Those skilled in the art may readily write such a control program based on the flow charts and other descriptions presented herein. It is to be understood and appreciated that the subject matter described herein includes not only devices and/or systems when programmed to perform various acts described below, but the software that is configured to program the controllers and, additionally, any and all computer-readable media on which such software might be embodied. Examples of such computer-readable media include, without limitation, floppy disks, hard disks, CDs, RAM, ROM, flash memory and the like.
Turbochargers are frequently utilized to increase the power output of an internal combustion engine. Referring to
As shown in
In general, the turbine stage 126 includes a turbine wheel (see, e.g., wheel 226 of
During operation, a turbocharger generates noise where the overall “sound quality” may be determined by its noise, vibration and harshness (NVH) characteristics. Conventional ball bearing systems have noted NVH issues. NVH issues can be attributed to factors such as inner race eccentricity, tolerances, balance, centering and assembly. Any of these factors can result in metal-to-metal contact between components (e.g., between a bearing and a housing). While lubricant films can damp some detrimental NVH energy, metal pin or end plate locating mechanisms readily transmit NVH energy. Complex loading can also generate axial vibration, which is often poorly damped.
Other components or features of the assembly 200 of
The turbine wheel 226 includes a seal mechanism 227 that acts to seal lubricant on a housing side and exhaust on an exhaust side of the assembly 200. In the example of
The compressor wheel 224 connects to the shaft 222 and is spaced axially from the bearing cartridge 220 by a collar 228 (e.g., a thrust collar). The collar 228 includes a seal mechanism 229 that acts to seal lubricant on a housing side and intake air on an intake side of the assembly 200. In the example of
As indicated by arrows, the assembly 200 is configured to receive lubricant at an inlet 206. Lubricant can then flow to the bore 213 and the bearing cartridge 220 via one or more lubricant paths. Lubricant can flow axially toward the compressor end 202 and the turbine end 204 and exit the housing 210 via the lubricant outlet 208 (see
During operation of the assembly 200, changes in conditions can cause the shaft 222 to exert axial forces (e.g., axial thrust). To maintain the bearing cartridge 220 in the bore 213, the clip 230 bridges the housing 210 and the outer race of the bearing 220. In addition, the clip 230 includes openings that allow lubricant to flow to, or from, the bearing cartridge 220 and the housing 210. For example, as shown in
A profile of the bearing cartridge 320 illustrates the slot 321 with respect to grooves, plateaus and surfaces with respect to the z-axis (e.g., axis of rotation). From the compressor end to the turbine end, the profile includes a cylindrical surface (EC) disposed at a radius rEC adjacent the compressor end, a groove (GC) adjacent the surface EC, a plateau (PC) disposed at a radius rPC adjacent the groove GC, a slot wall (SC) adjacent the plateau PC, a slot (length ΔzS), a slot wall (ST) defining in part the length of the slot (ΔzS), a plateau (PT) disposed at a radius rPT adjacent the slot wall ST, and a cylindrical surface (ET) disposed at a radius rET adjacent the turbine end.
The bearing cartridge 320 also includes a lubricant opening 323 positioned in the groove GC and a lubricant opening 323′ positioned in the groove GT. The lubricant openings 323, 323′ allow lubricant to flow to the inner portion of the bearing cartridge 320 (e.g., to lubricate balls, one or more journals, etc.). The bearing cartridge 320 further includes a series of openings 327 in a cylindrical wall disposed between the slot walls SC and ST that allow lubricant to flow to, or from, the inner portion of the bearing cartridge 320.
The clip 330 includes various features as illustrated in a perspective view. These features are described with respect to a cylindrical coordinate system that includes an axial dimension z, a radial dimension r and an azimuthal dimension θ. The clip 330 is generally shaped as a cylindrical wall (with a length or height Δz, approximately ΔzS) with a slit and made of a material capable of being deformed to change its overall circumference or maximal radial dimension. The material may be selected to reduce transmission of noise or vibration from the bearing cartridge 330 and a housing (e.g., the housing 210 of
In the example of
In the example of
In the example of
The assembly 300 shows the clip 330 positioned with respect to the slot 321 of the bearing cartridge 320. The clip 330 may be provided in a state that allows it to be positioned with respect to the slot 321 (e.g., an inner radius larger than the maximum outer radius of the bearing cartridge 320. Once positioned, the clip 330 may be compressed such that the clip 330 seats in the slot 321 (e.g., restrained in part by the walls SC and ST that define the slot 321). For insertion into a bore of a housing, the clip 330 may be further compressed to a dimension (e.g., diameter) smaller than that of the bore.
As described herein, an exemplary locating mechanism includes a unitary bearing outer race that has a central axis and that includes a turbine end, a compressor end and a slot, of an axial length, disposed between the turbine end and the compressor end; and a deformable clip shaped as a semi-cylindrical wall having an axial length less than the axial length of the slot, where, in a tension state, the clip has an inner circumference to position the clip with respect to the slot and where, in a compression state, the clip has an inner circumference that locates the clip in the slot. For example, in
After positioning, as the angle ΔΘ decreases, the inner circumference of the clip 330 decreases to locate the clip 330 in the slot 321. After locating the clip 330 with respect to the slot 321, the clip 330 may be compressed again to decrease the angle ΔΘ for positioning the bearing 320 and clip 330 into a bore of a housing. The clip 330 may be resilient and expand in a slot in the bore of the housing or, as explained below, an adjustment may be made to the clip 330 to increase its outer dimension (e.g., circumference or diameter) to locate it with respect to a slot in the bore of the housing. Hence, upon positioning the clip 330 in a bore of a housing, the clip 330 can have an outer circumference that locates the clip 330 in a slot of the bore of the housing.
As described herein, an exemplary method may perform the aforementioned acts to increase and decrease the inner circumference of the clip 330 with respect to the bearing 320. Such acts may be performed by machinery (e.g., robotic machinery) controlled by a computing device per processor executable instructions.
As described herein, an exemplary assembly includes a housing that includes a bore that has a slot; a bearing cartridge that includes an outer race that has a slot, an inner race and balls disposed between the outer race and the inner race; and a clip seated partially in the bore slot and partially in the outer race slot to retain the bearing cartridge in the bore of the housing. In this example, the clip can have a semi-cylindrical wall and optionally one or more lubricant openings. The clip may be made of a resin, which can act to reduce transmission of noise or vibration when compared to a metal clip. As indicated in
In the example of
In the arrangement of
As shown in
The assembly 800 of
As described herein, an exemplary assembly includes an integral ball bearing (inner ball races on shaft) and a retaining clip to space two corresponding outer ball races. In a particular example, an 8 mm bearing can be used with a Garrett® turbocharger having GT32 (e.g., compressor wheel diameter ˜71 mm and turbine wheel diameter ˜64 mm) or GT35 (e.g., compressor wheel diameter ˜71 mm and turbine wheel diameter ˜68 mm) frame sizes. The integral bearing can be a full complement cageless design with a spring system to load balls against ramps. In this assembly, the retaining clip can transmit axial thrust from the two piece outer bearing race to the center housing.
As described herein, an exemplary locating mechanism includes a first bearing outer race that includes a first shoulder; a second bearing outer race that includes a second shoulder; a deformable clip shaped as a semi-cylindrical wall having an axial length that defines a spacing between the first shoulder and the second shoulder; a spring to bias the first bearing outer race with respect to the second bearing outer race; and a shaft, inner race that cooperates with the first bearing outer race and the second bearing outer race and that can include an attachment mechanism for a turbine wheel at one end and an attachment mechanism for a compressor wheel at an opposing end. In such an example, the deformable clip may be made of resin.
As described herein, an exemplary assembly includes a housing that includes a bore that has a slot; a first bearing outer race that includes a first shoulder; a second bearing outer race that includes a second shoulder; a deformable clip shaped as a semi-cylindrical wall having an axial length that defines a spacing between the first shoulder and the second shoulder, that seats at least partially in the slot of the bore, that restricts at least some axial movement the first bearing outer race in the bore and that restricts at least some axial movement the second bearing outer race in the bore; a spring to bias the first bearing outer race with respect to the second bearing outer race; and a shaft, inner race that cooperates with the first bearing outer race and the second bearing outer race and that can include an attachment mechanism for a turbine wheel at one end and optionally an attachment mechanism for a compressor wheel at an opposing end.
The outer race 970 further includes a race surface 972 that cooperates with balls 925, an adjacent surface 973 that can receive lubricant via an opening 975 in the cylindrical wall of the outer race 970, a surface 974 that includes an opening 976 for lubricant flow to or from the space between the outer race 970 and the shaft 950.
The outer race 980 further includes a race surface 982 that cooperates with balls 925′, an adjacent surface 983 that can receive lubricant via an opening 985 in the cylindrical wall of the outer race 980, a step to a surface 984 and a step to a surface 986 that extends to the end surface 981, which, upon assembly, forms a gap with the surface 971 of the outer race 970.
As assembled, the outer race 980 receives a portion of the outer race 970 along the surface 986. A spring 960 may be positioned with respect to the outer race 970 and the outer race 980 to help maintain spacing, to absorb axial loads, etc. For example, a spring may be positioned with respect to the step between the surface 984 and the surface 986 of the outer race 980 to bias the outer race 970 (e.g., at an end surface 977).
As described herein, an exemplary assembly includes a first bearing outer race that includes a shoulder; a second bearing outer race that includes an end surface; a deformable clip shaped as a semi-cylindrical wall having an axial length that defines a spacing between the shoulder and the end surface; a spring to bias the first bearing outer race with respect to the second bearing outer race; and a shaft, inner race that cooperates with the first bearing outer race and the second bearing outer race via balls or other mechanism to allow for rotation of the shaft, inner race. In this example, the clip may be made of a resin. In this example, the clip and the spring can act cooperatively to absorb axial thrust forces exerted by the shaft, inner race and thereby reduce noise of the assembly during operation.
Although exemplary methods, devices, systems, etc., have 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 exemplary forms of implementing the claimed methods, devices, systems, etc.
Number | Name | Date | Kind |
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4679984 | Swihart et al. | Jul 1987 | A |
4726744 | Arnold | Feb 1988 | A |
4804316 | Fleury | Feb 1989 | A |
5653419 | Uchisawa et al. | Aug 1997 | A |
6269642 | Arnold et al. | Aug 2001 | B1 |
Number | Date | Country |
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2351534 | Mar 2001 | EP |
2001208077 | Aug 2001 | JP |
2004052933 | Feb 2004 | JP |
Number | Date | Country | |
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20100172739 A1 | Jul 2010 | US |