Abstract:
A system can include a shaft and turbine wheel assembly that includes a seal portion; a bearing assembly that includes an outer race and rolling elements that rotatably support the shaft and turbine wheel assembly; a sleeve that includes an outer diameter and a through bore that includes a first inner diameter that accommodates an outer diameter of the outer race of the bearing assembly and a second, smaller inner diameter that accommodates an outer diameter of the seal portion of the shaft and turbine wheel assembly; and a center housing that includes a compressor side, a turbine side and a bore that includes a turbine side bore diameter that accommodates the outer diameter of the sleeve.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of a co-pending U.S. patent application having Ser. No. 13/237,407, filed 20 Sep. 2011, which is incorporated by reference herein. 
     
    
     TECHNICAL FIELD 
       [0002]    Subject matter disclosed herein relates generally to turbomachinery for internal combustion engines and, in particular, to rotating assemblies. 
       BACKGROUND 
       [0003]    Exhaust driven turbochargers include a rotating group that includes a turbine wheel and a compressor wheel that are connected to one another by a shaft. The shaft is typically rotatably supported within a center housing by one or more bearings (e.g., oil lubricated, air bearings, ball bearings, magnetic bearings, etc.). During operation, exhaust from an internal combustion engine drives a turbocharger&#39;s turbine wheel, which, in turn, drives the compressor wheel to boost charge air to the internal combustion engine. 
         [0004]    During operation, a turbocharger&#39;s rotating group must operate through a wide range of speeds. Depending on factors such as size of the turbocharger, the maximum speed reached may be in excess of 200,000 rpm. A well balanced turbocharger rotating group is essential for proper rotordynamic performance. Efforts to achieve low levels of unbalance help to assure shaft stability and minimize rotor deflection which in turn acts to reduce bearing loads. Reduced bearing loads result in improved durability and reduced noise (e.g., as resulting from transmitted vibration). 
         [0005]    To reduce vibration, turbocharger rotating group balancing includes component and assembly balancing. Individual components such as the compressor and turbine wheel assembly are typically balanced using a low rotational speed process while an assembly is typically balanced using a high speed balancing process. In general, such an assembly includes a housing (e.g., a center housing) and is referred to as a center housing and rotating assembly (CHRA). 
         [0006]    Various balancing concerns stem from CHRA design, particularly characteristics of components that can dictate order of assembly. For example, many center housings are configured to receive a bearing via a compressor side opening and to receive a shaft via a turbine side opening. In such configurations, it makes sense to balance the shaft and the bearing once they are properly positioned in a center housing (e.g., as a CHRA). In other words, balancing a shaft and a bearing as an assembly (e.g., set in a jig) prior to insertion into the center housing does not necessarily ensure proper balance once these components are inserted into the center housing to form a CHRA. For example, where a press-fit is required between a race or rolling elements of a bearing and the shaft, it can be difficult to un-press-fit, insert in the components into center housing and re-press-fit the bearing and the shaft while achieving an exact realignment. 
         [0007]    Various technologies described herein pertain to assemblies that include a sleeve where the sleeve may be, for example, configured to support a bearing and shaft subassembly and to fit into a center housing. Such an approach can optionally facilitate balancing, minimize balance-related noise, vibration and harshness (NVH), etc. Such an approach may enhance stocking, manufacturing, inspection, maintenance, repair, and replacement (e.g., with components having same or different characteristics). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    A more complete understanding of the various methods, devices, assemblies, systems, arrangements, etc., described herein, and equivalents thereof, may be had by reference to the following detailed description when taken in conjunction with examples shown in the accompanying drawings where: 
           [0009]      FIG. 1  is a diagram of a turbocharger and an internal combustion engine along with a controller; 
           [0010]      FIG. 2  is a sectional exploded view of an example of a turbocharger rotational assembly that includes an example of a sleeve; 
           [0011]      FIG. 3  is a cross-sectional view of the assembly of  FIG. 2 ; 
           [0012]      FIG. 4  is a compressor end view of the assembly of  FIG. 3 ; 
           [0013]      FIG. 5  is a series of views of the example of the sleeve of  FIGS. 2 ,  3 , and  4  and another example of a sleeve; 
           [0014]      FIG. 6  is a series of views of components and a subassembly of the assembly of  FIGS. 2 ,  3  and  4 ; 
           [0015]      FIG. 7  is a series of views of components, a subassembly and a turbocharger rotational assembly; 
           [0016]      FIG. 8  is a block diagram of an example of a method to form various assemblies. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    As described herein, a sleeve can include a compressor end and a turbine end, a bore extending axially from the compressor end to the turbine end, a first counter bore that forms an axial face to axially locate a bearing in the bore, a second counter bore disposed axially between the first counter bore and the turbine end where the second counter bore includes a seal surface to form a lubricant and exhaust seal with a seal ring disposed about a shaft supported by a bearing, and a securing feature to secure the sleeve with respect to a turbocharger housing. 
         [0018]    As described herein, such a sleeve can provide for best practice high-volume manufacturing, optionally using conventional techniques. In other words, in a manufacturing process, a turbocharger rotating assembly that includes such a sleeve may be introduced while accommodating existing, in-place manufacturing techniques. 
         [0019]    As described herein, a sleeve can provide for increased manufacturing yield for rotating element bearing rotor groups (e.g., ball bearings, or other types of rolling element bearings). Use of a sleeve can allow for pre-assembly of various components, which, in turn, can enhance the benefits of balancing, for example, to minimize balance-related noise, vibration, and harshness (NVH). In general, such a sleeve may ease balancing costs, time, etc., for preassembled rotating element bearing rotor groups. 
         [0020]    As described herein, a sleeve-based approach can diversify range of turbocharger rotating element bearings and seals, for example, for aerodynamic applications. A sleeve-based approach can enable rolling element bearing and rotor group seal sizing to be designed independently from rolling element bearing diametral envelope size. For example, a sleeve-based approach can optionally permit use of a pre-assembled ball bearing and rotor group with any and all sizes of ball bearings or ball-on-shaft designs and seals. As described herein, a bearing and turbine seal bore insert can be its own fixture for pre-balance operations. Further, a sleeve-based approach can provide for rolling element bearing re-use, inspection, maintenance, replacement, etc. As described herein, a sleeve-based approach can result in reductions in development time, test trial time, stocking time, part tracking time, assembly time, inspection time, maintenance time, replacement time, etc. 
         [0021]    Below, an example of a turbocharged engine system is described followed by various examples of components, assemblies, methods, etc. 
         [0022]    Turbochargers are frequently utilized to increase output of an internal combustion engine. Referring to  FIG. 1 , a conventional system  100  includes an internal combustion engine  110  and a turbocharger  120 . The internal combustion engine  110  includes an engine block  118  housing one or more combustion chambers that operatively drive a shaft  112  (e.g., via pistons). As shown in  FIG. 1 , an intake port  114  provides a flow path for air to the engine block  118  while an exhaust port  116  provides a flow path for exhaust from the engine block  118 . 
         [0023]    Also shown in  FIG. 1 , the turbocharger  120  includes an air inlet  134 , a shaft  122 , a compressor  124 , a turbine  126 , a housing  128  and an exhaust outlet  136 . The housing  128  may be referred to as a center housing as it is disposed between the compressor  124  and the turbine  126 . The shaft  122  may be a shaft assembly that includes a variety of components. In operation, the turbocharger  120  acts to extract energy from exhaust of the internal combustion engine  110  by passing the exhaust through the turbine  126 . As shown, rotation of a turbine wheel  127  of the turbine  126  causes rotation of the shaft  122  and hence a compressor wheel  125  (e.g., impeller) of the compressor  124  to compress and enhance density of inlet air to the engine  110 . By introducing an optimum amount of fuel, the system  100  can extract more specific power out of the engine  100  (e.g., compared to a non-turbocharged engine of the same displacement). As to control of exhaust flow, in the example of  FIG. 1 , the turbocharger  120  includes a variable geometry unit  129  and a wastegate valve  135 . The variable geometry unit  129  may act to control flow of exhaust to the turbine wheel  127 . The wastegate valve (or simply wastegate)  135  is positioned proximate to the inlet of the turbine  126  and can be controlled to allow exhaust from the exhaust port  116  to bypass the turbine wheel  127 . 
         [0024]    Further, to provide for exhaust gas recirculation (EGR), such a system may include a conduit to direct exhaust to an intake path. As shown in the example of  FIG. 1 , the exhaust outlet  136  can include a branch  115  where flow through the branch  115  to the air inlet path  134  may be controlled via a valve  117 . In such an arrangement, exhaust may be provided upstream of the compressor  124 . 
         [0025]    In  FIG. 1 , an example of a controller  190  is shown as including one or more processors  192 , memory  194  and one or more interfaces  196 . Such a controller may include circuitry such as circuitry of an engine control unit. As described herein, various methods or techniques may optionally be implemented in conjunction with a controller, for example, through control logic. Control logic may depend on one or more engine operating conditions (e.g., turbo rpm, engine rpm, temperature, load, lubricant, cooling, etc.). For example, sensors may transmit information to the controller  190  via the one or more interfaces  196 . Control logic may rely on such information and, in turn, the controller  190  may output control signals to control engine operation. The controller  190  may be configured to control lubricant flow, temperature, a variable geometry assembly (e.g., variable geometry compressor or turbine), a wastegate, an exhaust gas recirculation valve, an electric motor, or one or more other components associated with an engine, a turbocharger (or turbochargers), etc. 
         [0026]      FIG. 2  shows an example of a turbocharger rotating assembly  200  that includes a shaft  220  supported by a bearing  230  disposed in a sleeve  240 , which may be inserted into a housing  280 . As shown in the example of  FIG. 2 , the shaft  220  extends to a turbine wheel  260  to form a shaft and wheel assembly (SWA) and a region that includes a seal mechanism  250  between the shaft  220  and the sleeve  240 . 
         [0027]    In the example of  FIG. 2 , the sleeve  240  includes an axial face  241  at a compressor end, one or more recessed outer surfaces  242 , one or more recessed axial faces  243 , an outer surface  244  and an axial face  246  at a turbine end. The axial face  241  at the compressor end includes various securing features  245 , which may be, for example, threaded sockets. The sleeve  240  further includes, disposed between the compressor end and the turbine end, an annular groove  247  to seat a seal component  270  (e.g., an O-ring) about a lubricant passage  248  and an annular groove  249  to seat a seal component  279  (e.g., a seal ring such as a piston ring). 
         [0028]    As to the housing  280 , it includes various features that allow for receipt of the sleeve  240  with the SWA (e.g., shaft  220  and turbine wheel  260 ). In the example of  FIG. 2 , the housing  280  includes an axial face  281  formed by a counterbore  282  at a compressor end. Adjacent to the counterbore  282  are one or more partial counterbores  283 , for example, that extend axially inwardly from the axial face  281  into a main bore  284 . As shown, the main bore  284  extends from the counterbore  282  to an axial face  286  at a turbine end of the housing  280 . Disposed along the main bore  284  is an annular groove  287  to seat a seal component (e.g., the seal component  270 ) about a lubricant passage  288 . Further, the housing  280  may include various cooling passages  289 , for example, to allow for transfer of heat energy away from the bore  284 . Also, at the compressor end of the housing  280 , securing features  285  exist for receipt of respective bolts  295 . 
         [0029]    As to cooperative features, the one or more recesses of the axial face  241  of the sleeve  240 , as defined by the one or more recessed outer surfaces  242 , may be oriented with respect to the one or more partial counterbores  283  of the housing  280 , for example, to allow the securing features  245  to align with the securing features  285  for insertion of bolts  295  to thereby secure the sleeve  240  with respect to the housing  280 . In such an example, the one or more partial counterbores  283  and the one or more recesses of the axial face  241  limit rotation of the sleeve  240  in the main bore  284  of the housing  280 , whether or not the bolts  295  are inserted. Accordingly, rotational forces transmitted to the sleeve  240  may be applied to the one or more partial counterbores  283 , which can reduce or prevent transmission of forces that could compromise the bolts  295  or the securing features  245  or  285  in a manner that could make disassembly difficult (e.g., bent bolts, stripped threads, etc.). 
         [0030]    In the example of  FIG. 2 , cooperation can also exist between the groove  247  of the sleeve  240  and the groove  287  of the housing  280 . Such an approach can help avoid misdirection of lubricant between the passages  248  and  288 , generally to occur from the passage  288  to the passage  248 . Further, the seal component  279  as seated in the groove  249  of the sleeve  240  can reduce transmission of exhaust from a turbine and transmission of lubricant, for example, given leakage of the seal component  270  or absence of such a seal component. While the example of  FIG. 2  shows an annular groove in the sleeve  240 , alternatively, or additionally, such a groove may be present in the main bore  284  of the housing  280 . Further, while both the sleeve  240  and the housing  280  are shown as including grooves for seating the seal component  270 , a groove in one of these components alone may be sufficient to seat a seal component. 
         [0031]      FIG. 3  shows a cross-sectional view of the assembly  200  of  FIG. 2  with the bearing  230  received by the sleeve  240  and the sleeve  240  received by the housing  280 . In the particular cross-sectional view, the axial face  241  of the sleeve  240  abuts the axial face  281  of the housing  280 . Further, various features of the seal mechanism  250  are shown. 
         [0032]    As to the bearing  230 , it includes an inner race  234 , rolling elements  235  and an outer race  236 , which may include a lubricant opening  238 . As shown, the shaft  220  is press-fit onto the inner race  234 ; accordingly, the shaft  220  and the inner race  234  rotate as a unit about the outer race  236 , which may optionally be fixed or otherwise limited in its ability to rotate within the sleeve  240  (e.g., via a locating or anti-rotation feature such as a pin). With respect to axial position of the bearing  230 , the outer race  236  is axially located by an axial face  255  of a counterbore  256  of the sleeve  240 . 
         [0033]    In the example of  FIG. 3 , the sleeve  240  also includes a lubricant passage  252 , which may have a larger cross-sectional area than the lubricant passage  248 . Further, an opening exists between an axial face  254  and an axial face  257 , which may provide for drainage of lubricant. 
         [0034]    As to the seal mechanism  250 , it may include a surface formed by a counterbore  258  of the sleeve  240 , an annular groove  265  in a portion of the shaft  220  and a seal component  275  seated at least partially in the groove  265 . As mentioned, another seal may be formed along the outer surface  244  of the sleeve  240  via a groove  249  and a seal component  279  seated at least partially in the groove  249 . Such a seal may act to reduce exhaust traveling in a direction toward the compressor and mixing with lubricant. Accordingly, as described herein, an assembly may include a concentric arrangement of seals that act to reduce passage of exhaust from an exhaust region of a turbocharger to one or more bores (e.g., a bore of a sleeve and a bore of a housing). In such an example, one seal is about a rotating component (i.e., the shaft) and the other seal is about a stationary component (i.e., the sleeve). 
         [0035]    In general, a seal about a rotating component may be more difficult to maintain and may be made with dimensions to minimize flow area, etc. Further, while single seals are shown in the example of  FIG. 3 , the seal between the sleeve  240  and the housing  280  or the seal between the shaft  220  and the sleeve  240  may rely on multiple grooves, seal components, etc. Yet further, both may rely on multiple grooves, seal components, etc. (e.g., to form labyrinths, etc.). 
         [0036]      FIG. 4  shows a compressor end view of the assembly  200  of  FIGS. 2 and 3 . In the example of  FIG. 4 , three bolts  295  are inserted into three openings  285  to secure the sleeve  240  in the housing  280 . 
         [0037]    As described herein, a turbocharger rotating assembly can include a bearing; a shaft and turbine wheel assembly supported by the bearing; a seal ring disposed about the shaft; and a sleeve that supports the bearing and that includes a compressor end and a turbine end, a bore extending axially from the compressor end to the turbine end, a first counter bore that forms an axial face that axially locates the bearing in the bore, a second counter bore disposed axially between the first counter bore and the turbine end where the second counter bore includes a seal surface that forms a lubricant and exhaust seal with the seal ring disposed about the shaft, and a securing feature to secure the sleeve with respect to a turbocharger housing. In such an assembly, the bearing, as axially located in the bore of the sleeve, may extend outward axially from the compressor end. As to a securing feature of a sleeve, one or more sockets may be disposed along an axial face of the sleeve at the compressor end. Further, a housing may include a socket disposed at a compressor end that aligns with a socket of a sleeve (e.g., for passing an end of a bolt). As described herein, a sleeve can optionally include an annular groove about an outer surface and a seal ring disposed in the annular groove (e.g., to form a seal between the sleeve and a bore of a housing in which the sleeve is to be inserted). 
         [0038]      FIG. 5  shows various views of the sleeve  240 , as shown in the examples of  FIGS. 2 ,  3  and  4 . Specifically,  FIG. 5  shows a perspective view of the sleeve  240 , a cross-sectional view of the sleeve  240  along a line A-A, a compressor end view of the sleeve  240  and a cross-sectional view of the sleeve  240  along a line B-B. Also shown in  FIG. 5  is a perspective view of an example of a sleeve  540  that does not include the groove  249  and, accordingly, the seal component  279 . As described herein, various features of a sleeve may be optional. 
         [0039]    In the compressor end view of the sleeve  240 , various radii are shown as extending from a z-axis as well as azimuthal angles about the z-axis. As shown, a radius of the counterbore  258  is less than a radius of the counterbore  256 , which is less than a radius of a bore  251 . Further, a radius of the recessed outer surface  242  is less than a radius of the outer surface  244 . Yet further, in the example of  FIG. 5 , various recesses  243  may be definable, in part, by respective azimuthal angles. 
         [0040]    As to axial dimensions, the cross-sectional view along the line B-B shows axial distances from the axial face  241  to an end of the bore  251 , to the axial face  255  and to the axial face  257 . 
         [0041]      FIG. 6  shows cross-sectional views of the bearing  230  (e.g., a bearing cartridge) and the sleeve  240 , as separate components and as an assembly with the seal component  270 , together with a compressor end view of the assembly with the seal component  270 . 
         [0042]    In the cross-sectional view of the assembly, axial dimensions Δz 1  and Δz 2  are shown with respect to the compressor end of the bearing  230  and the compressor end of the sleeve  240 . These dimensions depend on characteristics of the bearing  230  and the sleeve  240 . Specifically, the axial face  255  acts to axially locate the bearing  230  in the sleeve  240  and thereby may dictate extent of overhang. Overhang may depend on features of a turbocharger assembly such as thrust collar features, compressor backplate features, etc. 
         [0043]    As described herein, a bearing may include one or more openings that allow for passage of lubricant, for example, with respect to the sleeve  240 , from the passage  248  to shaft space, which may include one or more rolling elements (see, e.g., the balls  235 ). 
         [0044]      FIG. 7  shows cross-sectional views of the shaft  220  with the wheel  260 , the bearing  230  and the sleeve  240 . As indicated, a compressor end of the shaft  220  is inserted into the bearing  230 , as it is supported in the sleeve  240 , to form a turbocharger rotating assembly. 
         [0045]    As described herein, such an assembly may be balanced and then placed in a housing. Further, if some amount of unbalance is experienced (e.g., due to noise, vibration, etc.) after operation of a turbocharger, a compressor wheel may be removed from a compressor end of a shaft and access provided to any securing features that may secure a sleeve in a center housing to thereby allow for removal of the sleeve/bearing/SWA assembly. The assembly may then be subject to balancing or other inspection, maintenance, etc., and, if appropriate, reinstalled into the center housing. 
         [0046]      FIG. 8  shows a block diagram of an example of a method  800  that includes a provision block  810  for providing a sleeve with seal components, a bearing cartridge, a turbine shaft and wheel assembly, and a turbine seal ring (or rings); a position block  820  for positioning the bearing cartridge with respect to sleeve to form a sleeve and bearing cartridge assembly; an assembly block  830  for assembling the turbine seal ring (or rings) to the turbine shaft and wheel assembly; and an insertion block  840  for inserting the shaft of shaft and turbine wheel assembly with the seal ring (or rings) into the bearing cartridge assembly to form a sleeve assembly. In the example of  FIG. 8 , the method  800  can further include a provision block  850  for providing a housing with a bore; and a position block  860  for positioning the sleeve assembly into the bore of the housing. 
         [0047]    As described herein, positioning a sleeve assembly into a bore of a housing can form a seal (e.g., with one of multiple seal components) between the bore and the sleeve about a lubricant passage of the sleeve and form another seal, (e.g., with another one of the multiple seal components) between the sleeve and the bore of the housing (e.g., where the housing, sleeve or both may include features to seat a seal component or components). 
         [0048]    As described herein, various acts may be performed by a controller (see, e.g., the controller  190  of  FIG. 1 ), which may be a programmable control configured to operate according to instructions. As described herein, one or more computer-readable media may include processor-executable instructions to instruct a computer (e.g., controller or other computing device) to perform one or more acts described herein. A computer-readable medium may be a storage medium (e.g., a device such as a memory chip, memory card, storage disk, etc.). A controller may be able to access such a storage medium (e.g., via a wired or wireless interface) and load information (e.g., instructions and/or other information) into memory (see, e.g., the memory  194  of  FIG. 1 ). As described herein, a controller may be an engine control unit (ECU) or other control unit. Such a controller may optionally be programmed to control lubricant flow to a turbocharger, lubricant temperature, lubricant pressure, lubricant filtering, exhaust gas recirculation, etc. 
         [0049]    Although some examples of methods, devices, systems, arrangements, etc., have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the example embodiments disclosed are not limiting, but are capable of numerous rearrangements, modifications and substitutions without departing from the spirit set forth and defined by the following claims.