Patent Description:
A turbocharger can include a rotating group that includes a turbine wheel and a compressor wheel that are connected to one another by a shaft. For example, a turbine wheel can be welded or otherwise connected to a shaft to form a shaft and wheel assembly (SWA) and a compressor wheel can be fit to the free end of the shaft. An electric compressor can include one or more compressor wheels that are connected to a shaft or shafts that can be driven by an electric motor. As an example, a shaft that is attached to one or more bladed wheels may be supported by one or more bearings disposed in a bearing housing, which may form a center housing rotating assembly (CHRA). During operation of a turbocharger or an electric compressor, depending on factors such as size of various components, a shaft may be expected to rotate at speeds in excess of <NUM>,<NUM> rpm. To ensure proper rotordynamic performance, a rotating group should be well balanced, well supported and well lubricated over a wide range of conditions (e.g., operational, temperature, pressure, etc.). Similar turbocharger assemblies are known from the prior art <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

Aspects and preferred embodiments of the invention are defined in the appended claims.

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:.

Below, an example of a turbocharged engine system is described followed by various examples of components, assemblies, methods, etc..

Turbochargers are frequently utilized to increase output of an internal combustion engine. Referring to <FIG>, as an example, a system <NUM> can include an internal combustion engine <NUM> and a turbocharger <NUM>. As shown in <FIG>, the system <NUM> may be part of a vehicle <NUM> where the system <NUM> is disposed in an engine compartment and connected to an exhaust conduit <NUM> that directs exhaust to an exhaust outlet <NUM>, for example, located behind a passenger compartment <NUM>. In the example of <FIG>, a treatment unit <NUM> may be provided to treat exhaust (e.g., to reduce emissions via catalytic conversion of molecules, etc.).

As shown in <FIG>, the internal combustion engine <NUM> includes an engine block <NUM> housing one or more combustion chambers that operatively drive a shaft <NUM> (e.g., via pistons) as well as an intake port <NUM> that provides a flow path for air to the engine block <NUM> and an exhaust port <NUM> that provides a flow path for exhaust from the engine block <NUM>.

The turbocharger <NUM> can act to extract energy from the exhaust and to provide energy to intake air, which may be combined with fuel to form combustion gas. As shown in <FIG>, the turbocharger <NUM> includes an air inlet <NUM>, a shaft <NUM>, a compressor housing assembly <NUM> for a compressor wheel <NUM>, a turbine housing assembly <NUM> for a turbine wheel <NUM>, another housing assembly <NUM> and an exhaust outlet <NUM>. The housing assembly <NUM> may be referred to as a center housing assembly as it is disposed between the compressor housing assembly <NUM> and the turbine housing assembly <NUM>.

In <FIG>, the shaft <NUM> may be a shaft assembly that includes a variety of components (e.g., consider a shaft and wheel assembly (SWA) where the turbine wheel <NUM> is welded to the shaft <NUM>, etc.). As an example, the shaft <NUM> may be rotatably supported by a bearing system (e.g., journal bearing(s), rolling element bearing(s), etc.) disposed in the housing assembly <NUM> (e.g., in a bore defined by one or more bore walls) such that rotation of the turbine wheel <NUM> causes rotation of the compressor wheel <NUM> (e.g., as rotatably coupled by the shaft <NUM>). As an example a center housing rotating assembly (CHRA) can include the compressor wheel <NUM>, the turbine wheel <NUM>, the shaft <NUM>, the housing assembly <NUM> and various other components (e.g., a compressor side plate disposed at an axial location between the compressor wheel <NUM> and the housing assembly <NUM>).

In the example of <FIG>, a variable geometry assembly <NUM> is shown as being, in part, disposed between the housing assembly <NUM> and the housing assembly <NUM>. Such a variable geometry assembly may include vanes or other components to vary geometry of passages that lead to a turbine wheel space in the turbine housing assembly <NUM>. As an example, a variable geometry compressor assembly may be provided.

In the example of <FIG>, a wastegate valve (or simply wastegate) <NUM> is positioned proximate to an exhaust inlet of the turbine housing assembly <NUM>. The wastegate valve <NUM> can be controlled to allow at least some exhaust from the exhaust port <NUM> to bypass the turbine wheel <NUM>. Various wastegates, wastegate components, etc., may be applied to a conventional fixed nozzle turbine, a fixed-vaned nozzle turbine, a variable nozzle turbine, a twin scroll turbocharger, etc. As an example, a wastegate may be an internal wastegate (e.g., at least partially internal to a turbine housing). As an example, a wastegate may be an external wastegate (e.g., operatively coupled to a conduit in fluid communication with a turbine housing).

In the example of <FIG>, an exhaust gas recirculation (EGR) conduit <NUM> is also shown, which may be provided, optionally with one or more valves <NUM>, for example, to allow exhaust to flow to a position upstream the compressor wheel <NUM>.

<FIG> also shows an example arrangement <NUM> for flow of exhaust to an exhaust turbine housing assembly <NUM> and another example arrangement <NUM> for flow of exhaust to an exhaust turbine housing assembly <NUM>. In the arrangement <NUM>, a cylinder head <NUM> includes passages <NUM> within to direct exhaust from cylinders to the turbine housing assembly <NUM> while in the arrangement <NUM>, a manifold <NUM> provides for mounting of the turbine housing assembly <NUM>, for example, without any separate, intermediate length of exhaust piping. In the example arrangements <NUM> and <NUM>, the turbine housing assemblies <NUM> and <NUM> may be configured for use with a wastegate, variable geometry assembly, etc..

In <FIG>, an example of a controller <NUM> is shown as including one or more processors <NUM>, memory <NUM> and one or more interfaces <NUM>. Such a controller may include circuitry such as circuitry of an engine control unit (ECU). 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 <NUM> via the one or more interfaces <NUM>. Control logic may rely on such information and, in turn, the controller <NUM> may output control signals to control engine operation. The controller <NUM> may be configured to control lubricant flow, temperature, a variable geometry assembly (e.g., variable geometry compressor or turbine), a wastegate (e.g., via an actuator), an electric motor, or one or more other components associated with an engine, a turbocharger (or turbochargers), etc. As an example, the turbocharger <NUM> may include one or more actuators and/or one or more sensors <NUM> that may be, for example, coupled to an interface or interfaces <NUM> of the controller <NUM>. As an example, the wastegate <NUM> may be controlled by a controller that includes an actuator responsive to an electrical signal, a pressure signal, etc. As an example, an actuator for a wastegate may be a mechanical actuator, for example, that may operate without a need for electrical power (e.g., consider a mechanical actuator configured to respond to a pressure signal supplied via a conduit).

<FIG> shows a side view of an example of a turbocharger assembly <NUM> and <FIG> shows a turbine end view of the example of the turbocharger assembly <NUM>.

As shown, the turbocharger assembly <NUM> includes a shaft <NUM>, a compressor wheel <NUM>, a turbine wheel <NUM>, a center housing <NUM>, and a compressor plate <NUM>. As shown, the turbocharger assembly <NUM> also includes lubrication system features <NUM>, a pin socket features <NUM> and a pin <NUM>. In the example of <FIG>, the turbocharger assembly <NUM> can be oriented with respect to gravity, for example, to facilitate flow of lubricant due in part to gravity.

<FIG> shows lines A-A and C-C while <FIG> shows lines A-A and B-B. <FIG> shows a cross-sectional view of the turbocharger <NUM> along the line A-A; <FIG> shows a cross-sectional view of the turbocharger <NUM> along the line B-B; and <FIG> shows a cross-sectional view of the turbocharger <NUM> along the line C-C.

In <FIG>, the turbocharger assembly <NUM> is shown as including a nut <NUM> attached to the shaft <NUM> where the shaft <NUM> is part of a shaft and wheel assembly (SWA) that includes the turbine wheel <NUM>. For example, the turbine wheel <NUM> can include a hub portion <NUM> that is a transition portion between the shaft <NUM> and the turbine wheel <NUM>. As an example, the turbine wheel <NUM> can be welded or otherwise attached to the shaft <NUM> where various components are positioned along the shaft <NUM> such that tightening of the nut <NUM> acts to mechanically compress the compressor wheel <NUM> and cause rotation of the shaft <NUM> to rotate the compressor wheel <NUM>.

In the example of <FIG>, to reduce flow of exhaust inwardly into the center housing <NUM>, the hub portion <NUM> of the SWA can include one or more seal elements such as, for example, piston rings that are disposed between the hub portion <NUM> and a bore wall of a turbine side bore of the center housing <NUM>. To reduce flow of air inwardly into the center housing <NUM>, a thrust collar <NUM> (e.g., optionally with a lubricant slinger, etc.) can be disposed in a bore of the compressor plate <NUM> where one or more seal elements may be positioned between the thrust collar <NUM> and a bore wall of the bore of the compressor plate <NUM>.

In the example of <FIG>, the turbocharger assembly <NUM> includes a bearing assembly <NUM> that is disposed at least in part in a bore <NUM> defined by a bore wall <NUM> of the center housing <NUM>. As shown, the shaft <NUM> is rotatably supported by the bearing assembly <NUM> such that rotation of the turbine wheel <NUM> (e.g., via flow of exhaust) can drive rotation of the compressor wheel <NUM>.

The bearing assembly <NUM> is shown as being a rolling element bearing assembly (REB assembly) that can be lubricated via flow of lubrication via the lubrication system features <NUM>. In the example of <FIG>, the lubrication system features <NUM> include an opening <NUM> to a bore <NUM> in the center housing <NUM> that is in fluid communication with another opening <NUM>, which can be from an intersecting bore in the center housing <NUM>. As shown, the opening <NUM> can receive a plug <NUM> to seal the bore <NUM> (e.g., a seal element such as a ball, etc.) with respect to the opening <NUM> such that the bore <NUM> is supplied with lubricant via the opening <NUM>. As shown, the lubrication system features <NUM> include lubricant passages <NUM> and <NUM> where the lubricant passage <NUM> directs lubricant from the bore <NUM> toward the compressor side of the turbocharger assembly <NUM> and where the lubricant passage <NUM> directs lubricant from the bore <NUM> toward the turbine side of the turbocharger assembly <NUM>. In such an example, the lubricant passages <NUM> and <NUM> are supplied by a common bore (e.g., the bore <NUM>).

In the example of <FIG>, the bearing assembly <NUM> can include lubricant jets that can direct lubricant to rolling elements such as, for example, ball bearings, etc. Lubricant can flow from the bearing assembly <NUM> and the bore <NUM> via various passages such as a passage <NUM> in fluid communication with the bore <NUM>, a compressor side passage <NUM> and a turbine side passage <NUM> where lubricant can flow from such passages to a common lubricant outlet <NUM> of the center housing <NUM>. As an example, an internal combustion engine can include a lubricant pump (e.g., an oil pump, etc.) that can supply via a conduit lubricant to the turbocharger assembly <NUM> under pressure such that pressurized lubricant is received in the bore <NUM>. As the lubricant outlet <NUM> can be at a lower pressure than that of supplied lubricant, the lubricant system features <NUM> can provide for pressure-driven flow of lubricant. When supply pressure drops, for example, due to shutting down a lubricant pump, some remaining amount of lubricant may drain under flow of gravity, which may collect at or flow out via the lubricant outlet <NUM>. In such an example, as lubricant drains, one or more lubricant films between the bearing assembly <NUM> and the bore <NUM> of the center housing <NUM> can thin such that the bearing assembly <NUM> may come to rest on the bore wall <NUM>; noting that the bearing assembly <NUM> can carry the weight of various components such as the compressor wheel <NUM> and the turbine wheel <NUM> (e.g., and the thrust collar <NUM>, etc.). When a lubricant pump resumes operation, pressurized flow of lubricant via the lubricant system features <NUM> can cause lubricant films to form or thicken, as well as lubricant to flow to lubricant rolling elements of the bearing assembly <NUM>.

Lubricant can reduce friction between components, form lubricant films and transfer heat energy away from the turbocharger assembly <NUM>. However, in various instances, components can contact, which may result in noise, wear, vibration, etc. For example, where two components contact, the contacting force can result in noise, vibration and harshness (NVH).

NVH can be utilized to characterize vehicles, particularly cars and trucks. While noise and vibration may be measurable, harshness tends to be a subjective quality (e.g., measured via surveys, analytical tools that can provide results reflecting human subjective impressions, etc.), as may be part of the field of psychoacoustics. In various instances, engine-related noise (e.g., turbocharger noise) can present in an interior space (e.g., a cabin) of a vehicle, which may be annoying to one or more occupants of the vehicle.

In <FIG>, the turbocharger assembly <NUM> includes the pin <NUM> positioned with respect to the pin socket features <NUM>. In the example of <FIG>, the pin <NUM> can perform one or more functions. For example, the pin <NUM> can limit movement of at least a portion of the bearing assembly <NUM>. However, as mentioned, if two components contact each other, one or more NVH issues may arise. In the example of <FIG>, the pin <NUM> is shown as including features that can mitigate one or more NVH issues. For example, the pin <NUM> can provide for lubricant flow and/or lubricant film formation that can reduce incidence of one or more NVH issues, which can include one or more of rotational speed related issues, lubricant pressure related issues, thrust related issues, etc..

In the example of <FIG>, the bearing assembly <NUM> is shown as including an outer race <NUM>, an inner race <NUM> and rolling elements <NUM> that are disposed at least in part between the outer race <NUM> and the inner race <NUM>, for example, using a bearing retainer <NUM>. In the example of <FIG>, the inner race <NUM> may be optional, for example, consider a shaft that directly includes raceways for rolling elements; whereas, in <FIG>, the inner race <NUM> is fit to the shaft <NUM> where the inner race <NUM> includes raceways for the rolling elements <NUM>. Also, in the example of <FIG>, the bearing assembly <NUM> includes a compressor side set of rolling elements <NUM>-<NUM> with a corresponding bearing retainer <NUM>-<NUM> and a turbine side set of rolling elements <NUM>-<NUM> with a corresponding bearing retainer <NUM>-<NUM> and a multi-piece inner race <NUM>, which can include a compressor side inner race <NUM>-<NUM> and a turbine side inner race <NUM>-<NUM>.

As mentioned, the outer race <NUM> can include lubricant jets such as, for example, one or more compressor side lubricant jets and one or more turbine side lubricant jets, which can be supplied with lubricant via the passage <NUM> and the passage <NUM>, respectively, where the lubricant jets direct lubricant to the rolling elements <NUM>-<NUM> and the rolling elements <NUM>-<NUM>, respectively.

In the example of <FIG>, some lubricant regions are shown, including a lubricant film region <NUM>, a compressor side lubricant well region <NUM> and a turbine side lubricant well region <NUM>. As an example, the passage <NUM> can supply lubricant to the compressor side lubricant well region <NUM>, which can be in fluid communication with one or more compressor side lubricant jets of the outer race <NUM>, and the passage <NUM> can supply lubricant to the turbine side lubricant well region <NUM>, which can be in fluid communication with one or more turbine side lubricant jets of the outer race. As to the lubricant film region <NUM>, it may receive lubricant via one or more routes, which can be via the compressor side lubricant well region <NUM> and/or via the turbine side lubricant well region <NUM>. As shown, the lubricant well regions <NUM>, <NUM> and <NUM> span axial lengths and span azimuthal angles with respect to a rotational axis of the inner race <NUM>. For example, each of the lubricant regions <NUM>, <NUM> and <NUM> can span <NUM> degrees.

In the example of <FIG>, the maximum outer diameter of the outer race <NUM> as received in the bore <NUM> of the center housing <NUM> can be slightly less than the inner diameter of the bore wall <NUM> of the bore <NUM> of the center housing <NUM> such that one or more clearances are formed where lubricant can exist therein. For example, most of the outer surface of the outer race <NUM> can be coated with lubricant and most of the surface of the bore wall <NUM> can be coated with lubricant. In such an example, one or more lubricant regions can form one or more lubricant squeeze films, which can be sized to provide properties that aim to reduce NVH, etc. As an example, a lubricant squeeze film can be referred to as a squeeze film damper (SFD).

As an example, in a rolling element bearing assembly (REB assembly), a series of rolling elements can be placed between an inner race and an outer race where the inner race can be press fitted on a shaft and where the outer race is limited in its rotational movement by an anti-rotation pin. In such an example, a lubricant film that forms between the outer race and a bore wall of a bore of a center housing can be a squeeze film damper (SFD).

In another type of bearing system, referred to as a journal bearing system, a journal bearing (or journal bearings) can be utilized without rolling elements; noting that a hybrid approach may utilized a journal bearing and a REB assembly. As to a fully floating rotating journal bearing, it can utilize two hydrodynamic lubricant films disposed in series where one film is an inner film (between the shaft and journal bearing) and the other film is an outer film (between the journal bearing and center housing). As to a semi-floating journal bearing, it can include a hydrodynamic inner lubricant film and a squeeze film damper (SFD) (outer oil film, between the journal bearing and the center housing). While various examples mention use of a REB assembly, as an example, a semi-floating journal bearing may be utilized where, for example, the journal bearing includes an opening that can receive a pin such as, for example, the pin <NUM>. While various examples refer to a center housing, as an example, a component other than a center housing may be utilized to form a bore such as the bore <NUM> (e.g., consider a bearing housing, which may be a cartridge that can be received in a center housing, etc.).

As to the pin socket features <NUM>, <FIG> shows a pin socket or pin bore <NUM>, an opening <NUM>, an axial face <NUM> (e.g., a stop surface), a mating region <NUM> (e.g., for threading via threads, for interference fitting, etc.), a transition region <NUM>, and a lubricant well region <NUM> that can define one or more lubricant wells with respect to the pin <NUM>, for example, where the pin <NUM> is received at least in part in the lubricant well region <NUM>. In the example of <FIG>, the pin socket <NUM> can be formed as a cross-bore that intersects the bore <NUM> of the center housing <NUM>.

In the example of <FIG>, an opening <NUM> in the bore wall <NUM> of the bore <NUM> of the center housing <NUM> and the pin socket <NUM> can be defined by a perimeter formed by the intersection of two cylinders. The curves of intersection of two cylinders of radii "a" and "b" are given by the parametric equations in a Cartesian coordinate system (x, y, z): <MAT> <MAT> <MAT>.

In such an example, a bore of a housing can be of a radius "a" and a portion of a pin socket of the housing can be of a radius "b" where such "cylinders" may intersect at right angles (see also, e.g., <FIG>, <FIG>).

In the example of <FIG>, the pin <NUM> is shown as being at least in part received in an opening <NUM> of the outer race <NUM> of the bearing assembly <NUM> (e.g., consider intersecting "cylinders"). As the pin <NUM> is securely fit in the center housing <NUM> via the at least some of the pin socket features <NUM> (e.g., features of the mating region <NUM>, etc.), the pin <NUM> can be stationary. In contrast, the outer race <NUM> of the bearing assembly <NUM> can be semi-floating, for example, via one or more lubricant films (e.g., consider the lubricant regions <NUM>, <NUM> and <NUM>, etc.), while the pin <NUM>, as secured, limits rotational movement of the outer race <NUM>.

As mentioned, where components contact, one or more NVH issues may arise. For example, consider the outer race <NUM> rotating in the bore <NUM> of the center housing <NUM> such that a wall <NUM> of the outer race <NUM> that defines the opening <NUM> contacts the pin <NUM>. In such an example, contact between the wall <NUM> (e.g., a wall surface) and the pin <NUM> (e.g., an outer surface of the pin <NUM>) can occur with force sufficient to generate a noise (e.g., kinetic energy being transformed into acoustic energy).

Acoustic intensity, I, can have units of energy per unit area per unit time and acoustic energy density, w=I/c, can have units of energy per unit volume.

As an example, NVH can be periodic and/or random. For example, periodic NVH can be driven by a rotational speed (e.g., RPM) or one or more other periodic phenomena; whereas, random NVH can be driven by one or more random processes, which may be random or, for example, random in occurrence and periodic during occurrence, etc..

As an example, NVH can be caused by unbalance of one or more components. For example, consider a rotating assembly such as a center housing rotating assembly (CHRA) where the turbocharger assembly <NUM> can be a CHRA. In such an example, some amount of unbalance can exist for one or more components such as, for example, one or more of the compressor wheel <NUM>, the turbine wheel <NUM>, the thrust collar <NUM>, the inner race <NUM>, etc. As an example, unbalance may manifest in a manner that depends on one or more operational conditions such as, for example, rotational speed of a shaft, which may be a turbocharger shaft, a crankshaft of an internal combustion engine, etc. As an example, where lubricant flow is driven by a lubricant pump where the speed of the lubricant pump is variable (e.g., depending on crankshaft speed, etc.), NVH may depend on how the lubricant pump operates. As an example, at a low engine RPM (crankshaft RPM), a crankshaft driven lubricant pump may provide less pressure than at a higher engine RPM and, in such an example, the exhaust energy of the engine may relate to rotational speed of a turbine wheel as part of a SWA supported by a bearing (e.g., REB assembly, journal bearing, etc.).

As mentioned, the outer race <NUM> of the bearing assembly <NUM> can include the opening <NUM>, which can receive a portion of the pin <NUM>. To reduce risk of, occurrence of (e.g., frequency, etc.) and/or magnitude of one or more NSV issues, the pin <NUM> can include grooves that are positioned to deliver some amount of lubricant from a clearance region between the outer race <NUM> and the bore wall <NUM> of the center housing <NUM> to an interface between the pin <NUM> and the wall <NUM> of the outer race <NUM> that defines the opening <NUM>. In such an example, the lubricant at the interface can provide for energy damping such that kinematics are favorably altered. For example, consider damping vibration, which can include vibration that would get transmitted from the outer race <NUM> to the center housing <NUM> via the pin <NUM>.

As mentioned, the pin <NUM> may provide for one or more of anti-rotation (e.g., rotation limiting) and anti-axial translation (e.g., translation limiting). Where one type of motion causes undesirable behavior, one or more grooves may be provided that mitigate that undesirable behavior. For example, consider clockwise rotation where a groove is positioned to damp contact from such clockwise rotation, which may be dependent on turbocharger behavior, including intended direction of rotation of a turbine wheel responsive to flow of exhaust. As another example, consider counter-clockwise rotation where a groove is positioned to damp contact from such counter-clockwise rotation, which may be dependent on turbocharger behavior, including intended direction of rotation of a turbine wheel responsive to flow of exhaust. As yet another example, consider a groove is positioned to damp contact from axial translation toward a compressor side of a turbocharger, which may be dependent on turbocharger behavior, including intended direction of rotation of a turbine wheel responsive to flow of exhaust. As yet another example, consider a groove is positioned to damp contact from axial translation toward a turbine side of a turbocharger, which may be dependent on turbocharger behavior, including intended direction of rotation of a turbine wheel responsive to flow of exhaust. As an example, a pin can include one or more grooves where each of the grooves may be to address one or more particular types of motion. As an example, a pin can include four grooves that may be sufficient to address the foregoing four types of contact. As an example, shape and/or size and/or number of grooves may differ for different types of motion (e.g., different types of contact).

As an example, a pin may include a symmetric arrangement of grooves and/or an asymmetric arrangement of grooves. As to a symmetric arrangement, consider four grooves at <NUM>, <NUM>, <NUM> and <NUM> degrees about an axis of a pin. In such an example, the pin may be positioned into an opening of an outer race (e.g., or journal) where two of the grooves are aligned substantially axially along an axis parallel to an axis of rotation of a shaft and the other two of the grooves are aligned along a cross-axis, parallel and orthogonal to the axis of rotation of the shaft. To facilitate alignment, a pin can include a marker, markers, etc., which may be at a top of the pin (e.g., a head portion of the pin). For example, a pin can include an indicator (e.g., a mark) that is to be substantially aligned in a direction toward a compressor side or a turbine side. Where a pin includes symmetry of grooves, the indicator may be suitable for substantial alignment toward a compressor side or a turbine side. While compressor side and turbine side are mentioned, referring to <FIG>, the center housing <NUM> can include one or more features to facilitate positioning of a pin for alignment of the pin about an axis of the pin with respect to an outer race (e.g., or journal). For example, consider positioning a pin with a marker pointing down in <FIG> (e.g., in the direction of gravity) or with a marker pointing up in <FIG>. As an example, one or more fiducials (e.g., fiducial markers) can be utilized to facilitate positioning of a pin in a center housing such that one or more features of the pin (e.g., one or more grooves) are sufficiently aligned to mitigate one or more types of NVH issues.

<FIG> shows a cross-sectional, cut-away view of a portion of the turbocharger assembly <NUM> where the pin <NUM> includes a head <NUM>, an optional marker <NUM>, an optional drive feature <NUM>, an axial face <NUM> (e.g., a stop surface), a mating region <NUM>, a transition region <NUM>, a groove portion <NUM> with one or more grooves that span an axial length along the pin <NUM>, as may be indicated by the dimension □zg, an end portion <NUM> and an end surface <NUM>. In the example of <FIG>, two grooves are visible, noting that one or more other grooves may be presented, where the two grooves are of approximately equal dimensions.

As explained, the center housing <NUM> can include the pin socket features <NUM> that can facilitate acceptable positioning of the pin <NUM> in the center housing <NUM>. For example, the axial face <NUM> can be utilized to axially locate the pin <NUM> via the axial face <NUM> of the pin <NUM> such that an end <NUM> of the pin <NUM> extends a desired depth into the bore <NUM> of the center housing <NUM> and/or the outer race <NUM> of the bearing assembly <NUM>. As shown, the depth may be measured, for example, using a longitudinal axis of the bore <NUM>, as indicated by the dimension □zz. The example of <FIG> shows another dimension which is an axial dimension, □ze, of the end portion <NUM> of the pin <NUM> along the axis of the pin <NUM>. As shown in the example of <FIG>, each of the two grooves extends into the opening <NUM> of the outer race <NUM> of the bearing assembly <NUM> and the end surface <NUM> of the pin <NUM> does not contact the inner race <NUM> of the bearing assembly <NUM> (e.g., a clearance exists between the end surface <NUM> of the pin <NUM> and an outer surface of the inner race <NUM>).

In the example of <FIG>, the pin <NUM> can include one or more types of features along at least a portion of the mating region <NUM> that can mate with one or more types of features along at least a portion of the mating region <NUM> of the pin socket <NUM>. Features may include, for example, one or more pilots, one or more threads, one or more interference fit surfaces, etc. As an example, the pin <NUM> can be threaded along at least a portion of the mating region <NUM> with threads that mate with corresponding threads along at least a portion of the mating region <NUM>. As an example, the pin <NUM> may be threadless and the pin socket <NUM> may be threadless such that the pin <NUM> is fit via an interference fit via interference surfaces along at least a portion of the mating region <NUM> and along at least a portion of the mating region <NUM>. In either example, where the pin <NUM> is provided with the marker <NUM>, the marker <NUM> may be oriented such that one or more grooves of the pin <NUM> are suitably oriented with respect to the bore <NUM> (e.g., with respect to a bore axis, etc.).

<FIG> shows a side view of an example of the pin <NUM>, which shows the head <NUM>, the axial face <NUM>, the mating region <NUM>, a transition region <NUM>, the groove portion <NUM>, the end portion <NUM> and the end surface <NUM>, where a chamfer <NUM> (e.g., annular, conical surface, etc.) can be present as a transition from a diameter of the end portion <NUM> to a smaller diameter of the end surface <NUM>. In <FIG>, the pin <NUM> is shown with a groove <NUM>, which can be defined by an axial length along the pin axis and a cross-dimension, shown as □g. The cross-dimension may be measured using a straight distance, an arc distance, and/or an angle. As shown, the cross-dimension is shown as being a maximum cross-dimension, which is approximately centered along the axial length of the groove <NUM>. In the example of <FIG>, the groove <NUM> is shown as being substantially symmetric along a longitudinal axis, where the groove <NUM> may be formed into the pin <NUM> via one or more types of techniques. As an example, the groove <NUM> may be formed via a machining technique, for example, using a grinding wheel with a V-shaped edge profile (see, e.g., Figs. 13A and 13B, etc.).

<FIG> shows a cross-sectional view of the pin <NUM> along the line D-D as illustrated in <FIG>. In the example of <FIG>, grooves <NUM> and <NUM> are shown, which can be spaced at approximately <NUM> degrees clockwise and counter-clockwise, respectively, from the groove <NUM> of the example of <FIG>. As shown, the groove <NUM> may be defined by a radius RG as measured a distance R from a pin axis zp.

<FIG> shows a cross-sectional view of the pin <NUM> along the line E-E as illustrated in <FIG>. In the example of <FIG>, grooves <NUM>, <NUM>, <NUM> and <NUM> are shown, which are arranged at approximately <NUM>, <NUM>, <NUM> and <NUM> degrees about the pin axis zp (e.g., spacing of □g = <NUM> degrees). As shown in the example of <FIG>, the groove <NUM> can be defined using the dimension RG, an angle □g and a radial depth □rg, as measured from a diameter of the pin <NUM> to the pin axis zp.

<FIG> shows the pin <NUM> in a cross-sectional view that is through a portion of the outer race <NUM> of the bearing assembly <NUM>, which is at a lower axial position than the cross-sectional view of <FIG>, as can be discerned by the sizes of the grooves <NUM>, <NUM>, <NUM> and <NUM> (see, e.g., <FIG>). As shown in <FIG>, a maximum radial depth (□rg) of a groove can be at an axial position along the pin axis zp that, when the pin <NUM> is positioned, is within the pin socket <NUM> and where a portion of the groove extends axially along the pin axis zp past the pin socket <NUM> (e.g., out of the pin socket <NUM> and into the bore <NUM>). In such an approach, a groove can be a reservoir with an opening that can be in fluid communication with lubricant of a film defined in a clearance between an outer surface of an outer race and an inner surface of a bore wall of a bore. In such an example, the dimensions of the groove, in combination with pin position with respect to a pin socket, can define a size of an opening relative to a reservoir volume where lubricant can flow into and out of the reservoir volume via the sized opening.

As an example, a groove reservoir and a reservoir opening may be sized with a priori knowledge of dynamics that may occur during operation of a turbocharger. For example, upon clockwise rotation of an outer race, lubricant pressure in the groove reservoir may decrease and/or lubricant volume in the groove reservoir may decrease (e.g., as lubricant may flow from the groove reservoir via the reservoir opening to another space) and, for example, upon counter-clockwise rotation of an outer race, lubricant pressure in the groove reservoir may increase and/or lubricant volume in the groove reservoir may increase (e.g., as lubricant may flow into the groove reservoir via the reservoir opening from another space). Such hydrodynamics can act to damp rotational movement (e.g., clockwise and/or counter-clockwise) of an outer race with respect to a pin that is received at least in part in an opening in the outer race. Such damping can help to reduce risk of one or more types of NVH, reduce occurrence of one or more types of NVH, and/or reduce magnitude (e.g., impact) of one or more types of NVH.

Referring again to <FIG>, a clearance region <NUM> is illustrated along with groove regions <NUM>, <NUM>, <NUM> and <NUM> where the regions <NUM>, <NUM>, <NUM>, <NUM> and <NUM> can receive lubricant (e.g., fill with lubricant). <FIG> also shows the opening <NUM> of the outer race <NUM> (e.g., as defined by a surface of the outer race <NUM>) and an outer surface <NUM> of the groove region <NUM> of the pin <NUM>.

In the example of <FIG>, a turbine side <NUM> is shown along with a compressor side <NUM>. In such an example, axial thrust can drive the outer race <NUM> toward the compressor side <NUM> or toward the turbine side <NUM>, where the dynamics of such axial thrust and its direction can differ. As explained, the outer race <NUM> may rotate, either clockwise or counter-clockwise, where the dynamics can differ.

In the example of <FIG>, the regions <NUM> and <NUM> can provide for some amount of damping for axial thrust that causes at least translational movement of the outer race <NUM> (e.g., along an axis directed from the compressor side <NUM> to the turbine side <NUM>) while the regions <NUM> and <NUM> can provide for some amount of damping for rotation (e.g., clockwise or counter-clockwise about the axis directed from the compressor side <NUM> to the turbine side <NUM>). As mentioned, a pin can include one or more grooves where each groove may correspond to a particular type or types of movement that may give rise to one or more NVH issues. While the example of <FIG> shows the regions <NUM>, <NUM>, <NUM> and <NUM> numbering four in total and being spaced at approximately <NUM> degrees about the pin axis zp, where an issue is determined to be for one of the aforementioned four types of movements, a pin may include a single groove or grooves arranged to address that one type of movement.

<FIG> shows an enlarged view of a portion of the cross-sectional view of <FIG> and <FIG> shows an enlarged view of a portion of the cross-sectional view of <FIG>. The grooves <NUM>, <NUM>, <NUM> and <NUM> can provide space for lubricant and may form lubricant reservoirs that can supply lubricant to the lubricant film region <NUM> and/or receive lubricant from the lubricant film region <NUM>.

As shown, in <FIG>, due to the "intersecting cylinders" geometry, the grooves <NUM> and <NUM> do not extend as deeply into the opening <NUM> of the outer race <NUM> as do the grooves <NUM> and <NUM>, all of which are in fluid communication with the lubricant film region <NUM>. As an example, a pin can include grooves with different dimensions, shapes, positions, etc. For example, where it is desirable to have each groove extend a common depth into an opening of an outer race (e.g., or journal), the cross-axis grooves (see, e.g., the grooves <NUM> and <NUM>) may be positioned lower than the axis grooves (see, e.g., the grooves <NUM> and <NUM>) or, stated otherwise, the axis grooves may be positioned higher. Again, due to the intersection of two cylinders geometry, the axis grooves "see" the maximum radius of the outer race <NUM> as they are shown to be aligned along the longitudinal axis of the outer race <NUM> while the cross-axis grooves "see" radii that are less than the maximum of the outer race <NUM> as they are shown to be offset from the longitudinal axis of the outer race <NUM>. As an example, a pin can include grooves that are designed for or over designed for axis or cross-axis positioning. As an example, a pin can include grooves that are limited in groove volume (e.g., individual or total) such that lubricant film dynamics are not detrimentally, undesirably altered (see, e.g., the lubricant film region <NUM>, which is in fluid communication with the grooves <NUM>, <NUM>, <NUM> and <NUM>).

As shown in <FIG>, the groove <NUM> can be facing upwardly and concave such that it can retain lubricant that is not amenable to drainage from the groove <NUM> due to gravity, where gravity is indicated to be in the direction shown in <FIG>. In such an example, the lubricant volume of the groove <NUM> may be designed accordingly. Further, the lubricant retained in the groove <NUM> may help to lubricate the interface between the pin <NUM> and the outer race <NUM> when the turbocharger assembly <NUM> is not operational; whereas, without the groove <NUM>, direct contact may occur between an outer surface of a pin and a surface of an opening of an outer race, which may be detrimental for one or more reasons (e.g., sticking, coking of lubricant, etc.).

<FIG> shows a perspective view of a portion of the pin <NUM> and a portion of the bearing assembly <NUM>. As shown in the example of <FIG>, the outer race <NUM> includes a keyway <NUM>, which is shown in <FIG> as being on a compressor side of the bearing assembly <NUM>. Such a keyway may be utilized with a key as a mechanism to limit movement of the outer race <NUM>, which may be additional to the use of the pin <NUM>. As shown, the outer race <NUM> can include various features such as a recessed substantially annular region <NUM> disposed axially between lubricant wells <NUM> and <NUM> as separated from the annular region <NUM> by regions <NUM> and <NUM>, respectively. As explained, when disposed in the bore <NUM> of the housing <NUM>, the annular region <NUM> can define the lubricant film region <NUM>, which can be in fluid communication with the grooves <NUM>, <NUM>, <NUM> and <NUM> of the pin <NUM>. As explained, the grooves <NUM> and <NUM> extend deeper into the opening <NUM> of the outer race <NUM> than do the grooves <NUM> and <NUM>; noting that groove dimensions, positions, etc., may be adjusted to provide for desired depth(s).

<FIG> shows the pin <NUM> as viewed from inside the outer race <NUM> where a portion of the end portion <NUM> and the end surface <NUM> are visible. In the example of <FIG>, the groves <NUM>, <NUM>, <NUM> and <NUM> are not visible as they do not extend to or past the opening <NUM> at the inner surface of the outer race <NUM>.

<FIG> shows the pin <NUM> as viewed from inside the bore <NUM> of the housing <NUM> where the opening <NUM> in the bore wall <NUM> of the housing <NUM> is shown with the pin <NUM> extending in part therethrough such that the groove <NUM> (e.g., oriented toward the compressor side) is partially visible while another portion of the groove <NUM> defines a groove reservoir with respect to the lubricant well region <NUM>, which is defined by a surface of the pin socket <NUM> in the housing <NUM>.

In the example of <FIG>, the visible portion of the groove <NUM> may be referred to as a groove opening or groove reservoir opening that is in fluid communication with a groove reservoir as defined in part by another portion of the groove <NUM> and a surface of a pin socket <NUM>. As mentioned, lubricant may flow to and/or from the lubricant film region <NUM> and one or more grooves of a pin to address one or more NVH issues.

<FIG> shows an example of a portion of a bearing <NUM>, which may be a journal or an outer race of a rolling element bearing assembly (REB assembly). As shown, the bearing <NUM> includes a wall <NUM> (e.g., a pin opening surface) that forms a shoulder with respect to a surface <NUM> (e.g., a cylindrical surface) and another shoulder with respect to an inner surface <NUM> where the wall <NUM> defines an opening <NUM> (e.g., a cross-bore to a main bore of the bearing <NUM>, etc.), which can be dimensioned to receive a pin such as, for example, the pin <NUM> or, for example, a pin with fewer grooves, more grooves, no grooves, etc..

In the example of <FIG>, the wall <NUM> can have a varying thickness as it is formed by an intersection of a cylinder with an annular cylinder. In such an example, the thickness can be greater "off-axis" when compared to "on-axis". As shown in the example of <FIG>, the bearing <NUM> can include one or more grooves <NUM>, <NUM>, <NUM> and <NUM> in the wall <NUM>, which can be at one or more positions, including, for example, one or more off-axis positions and/or one or more on-axis positions. In the example of <FIG>, the grooves <NUM> and <NUM> are on-axis while the grooves <NUM> and <NUM> are off-axis. As shown, a groove may be defined by a length L, a depth d, an opening width b and side dimensions such as a and c.

In the example of <FIG>, each of the grooves may be approximated as a V-shaped groove, which can have, for example, a depth d that varies over the length L. For example, if L is measured from the surface <NUM>, then the depth d diminishes with length, along with the opening width b and the side dimensions a and c. As an example, the shape of a groove may depend on a tool or tools utilized to form the groove and/or a process or processes utilized to form the groove (see, e.g., <FIG> and <FIG>).

As mentioned, forces, contact, NVH, etc., can be directional, which may be an on-axis direction, an off-axis direction or another direction. As explained, a groove can be positioned and/or dimensioned (e.g., sized, shaped, etc.) to address a particular issue. As to a bearing, it may be configured for orientation in a limited number of ways in a bore of a housing. For example, a bearing may be symmetric such that either end may be a compressor side end and either end may be a turbine side end. Alternatively, a bearing may be asymmetric in that it has a compressor side end that is to be on the compressor side of a bore of a housing and/or it has a turbine side end that is to be on the turbine side of a bore of a housing.

In the example of <FIG>, the on-axis grooves <NUM> and <NUM> are shown to be larger than the off-axis grooves <NUM> and <NUM>. Such an approach may match overlap with a pin that includes four equal sized grooves where due to the geometry of the opening <NUM> the overlap is less for the off-axis grooves and more for the on-axis grooves.

As explained, a pin with one or more grooves may be oriented in a desired orientation using one or more guides, which may include a marker, an inspection tool, etc., such that a groove is oriented as desired (e.g., aligned with an on-axis, aligned with an off-axis, etc.). As to the bearing <NUM>, orientation may be simpler and, in many instances, assured (e.g., for an asymmetric bearing, etc.).

As mentioned, an assembly can include a pin with at least one groove and/or a bearing with at least one groove. In such an assembly, where a pin is grooved and a bearing is grooved, grooves may align or not.

In the example of <FIG>, a clearance region <NUM> is illustrated along with groove regions <NUM>, <NUM>, <NUM> and <NUM>, which can receive lubricant (e.g., fill with lubricant). <FIG> also shows the opening <NUM> of the bearing <NUM> (e.g., as defined by the wall <NUM> and the surface <NUM>) and an outer surface <NUM> of a region <NUM> of a pin, which does not include grooves (e.g., at least at the level shown in the cross-sectional view of <FIG>).

In the example of <FIG>, a turbine side <NUM> is shown along with a compressor side <NUM>. In such an example, axial thrust can drive the bearing <NUM> toward the compressor side <NUM> or toward the turbine side <NUM>, where the dynamics of such axial thrust and its direction can differ. As explained, the bearing <NUM> may rotate, either clockwise or counter-clockwise, where the dynamics can differ.

In the example of <FIG>, the regions <NUM> and <NUM> can provide for some amount of damping for axial thrust that causes at least translational movement of the bearing <NUM> (e.g., along an axis directed from the compressor side <NUM> to the turbine side <NUM>) while the regions <NUM> and <NUM> can provide for some amount of damping for rotation (e.g., clockwise or counter-clockwise about the axis directed from the compressor side <NUM> to the turbine side <NUM>).

As mentioned, a pin and/or a bearing can include one or more grooves where each groove may correspond to a particular type or types of movement that may give rise to one or more NVH issues. While the example of <FIG> shows the regions <NUM>, <NUM>, <NUM> and <NUM> numbering four in total and being spaced at approximately <NUM> degrees about the opening <NUM>, where an issue is determined to be for one of the aforementioned four types of movements, a bearing may include a single groove or grooves arranged to address that one type of movement.

As explained, bearings of turbochargers can give rise to one or more types of NVH issues. For example, rolling elements rotating at or near a critical speed may tend to produce an objectionable whine especially under conditions when the engine noise is not loud enough to mask the turbocharger noise such as at idle. As explained, at idle, the engine may be at a particular low revolution speed as to a crankshaft operatively coupled to pistons. Further, depending on the configuration for lubricant pumping, lubricant pressure may be lower than at non-idle, higher engine RPMs.

Various types of NVH issue can be the most severe under cold start conditions when the engine and engine lubricant are both cold (e.g., at ambient temperature or otherwise much less than the operational temperature of the engine). As an example, a grooved pin and/or a grooved bearing can help to reduce or eliminate objectionable noise generated by a turbocharger under cold idle conditions.

<FIG> shows an example of a vehicle <NUM> with a turbocharger <NUM> that includes a turbocharger assembly such as, for example, the turbocharger assembly <NUM>. In such an example, testing may be performed to characterize objectionable NVH, which may be plotted as energy or other parameter versus RPM, which may be engine RPM, turbocharger shaft RPM, etc. <FIG> shows an example plot <NUM> of trial data for a turbocharged engine with and without a grooved pin (e.g., an ungrooved pin and a grooved pin). As shown, the characteristics of NVH can be altered using a grooved pin. In particular, rapid shifts in energy can be mitigated where such rapid shift can correspond to bearing/pin phenomena over a range of engine RPM, which may be or include, for example, engine idle RPM. In such an approach, rather than altering what may be otherwise an optimal engine idle RPM, a pin can be grooved or a grooved pin provided that mitigates undesirable NVH.

<FIG> shows an example of a grinding wheel <NUM> that includes an end profile suitable for forming one or more grooves in a pin. <FIG> shows a cross-sectional view of an example of a pin <NUM>, which may be a stock or blank suitable for use without grooves whereby the grinding wheel <NUM> can be utilized to form one or more grooves in the pin <NUM> and <FIG> shows a cross-sectional view of an example of the bearing outer race <NUM>, as including various features.

In <FIG>, various dimensions are shown, including a wheel diameter D, a hole diameter H, a profile length X, a profile width U, and a profile angle V°. Such dimensions can be parameters of a grinding wheel (e.g., a cutting wheel, etc.) or other tool that can be utilized to form a groove or grooves in a pin or in a bearing.

In <FIG>, various dimensions are shown, including a pin length LP in a direction along a pin axis zp and a pin diameter DP along a portion of the pin <NUM> where one or more grooves can be formed. In the example of <FIG>, the grinding wheel <NUM> is brought into contact with the pin <NUM> in a plane that includes the pin axis zp; noting that contact to form a groove may be with the plane of the grinding wheel <NUM> offset from the pin axis zp.

In the example of <FIG>, which does not form part of the present invention, the features of the bearing <NUM> include a compressor side end <NUM>, a turbine side end <NUM> along with lubricant jet openings <NUM>-<NUM> and <NUM>-<NUM>, which align with the lubricant wells <NUM> and <NUM>, respectively. Various dimensions are shown in <FIG>, including a pin opening axis zpo, a bearing length LB, a bearing outer diameter ODB at the lubricant film forming surface <NUM>, which is adjacent to the pin opening <NUM>, an a bearing inner diameter IDB, which is at an axial portion of the bearing <NUM> that is within the span of the lubricant film forming surface <NUM> such that at the pin opening <NUM>, the bearing <NUM> has thicknesses that may be defined in part by ODB from IDB. For example, in the cross-sectional view of <FIG>, the thickness may be defined as an on-axis thickness by subtracting ODB from IDB and dividing the result by <NUM> (e.g., (ODB-IDB)/<NUM>); however, as mentioned, the wall of the pin opening <NUM> may not be constant due to geometry of intersecting cylinders where, for a given ODB and IDB, the off-axis thickness is greater than the on-axis thickness. Where off-axis and on-axis grooves are formed in a bearing, groove length with respect to thickness of a wall that defines a pin opening may be taken into account, for example, to address short circuiting of lubricant flow (e.g., a groove that is not facing a pin surface and/or a groove that extends to IDB). As an example, groove length along a wall that defines a pin opening may be varied in the axial direction (on-axis) and anti-rotational direction (off-axis), for example, to reach a certain fraction or percent of a bearing thickness and/or wall thickness, which may be to provide a groove that does not break through to an inner surface at IDs. As an example, consider limiting groove length to <NUM> percent of a bearing thickness (e.g., (ODB-IDB)/<NUM>) and/or limiting groove length to <NUM> percent of a wall thickness of a wall that defines a pin opening. In such examples, the groove length limit may be lesser (e.g., yet sufficient to address one or more NVH issues) or may be greater, for example, to approximately <NUM> percent to provide greater interface coverage, though with some possible amount of increase in lubricant leakage from the interface to an axial, longitudinal bore of the bearing (e.g., where lubricant flow from a break-through groove would be lubricant short circuiting).

<FIG> also shows an example of the grinding wheel <NUM> (e.g., as appropriately sized, shaped, aligned, etc.) as being inserted at least in part in the opening <NUM> to form one or more grooves. For example, consider aligning a plane of a grinding wheel on-axis to form one or two grooves (e.g., optionally two grooves simultaneously), aligning a plane of a grinding wheel off-axis to form one or two grooves (e.g., optionally two grooves simultaneously), and/or aligning a plane of a grinding wheel at a desired angle to form one or more grooves, etc..

As an example, the same grinding wheel may be suitably sized for forming pin grooves and for forming bearing grooves. As an example, different types, sizes, shaped tools, etc., may be utilized to form one or more grooves.

As an example, one or more grooves may be formed according to one or more specifications, which can include position, depth of cut, length of cut, width, etc. As an example, a depth of cut may be less than approximately <NUM> and may be less than approximately <NUM>. As an example, a method can include utilizing a roughing grinding wheel and then a finishing grinding wheel, which can be rated as to grit size, etc..

<FIG> shows some examples of profiles <NUM> that may be utilized for forming one or more grooves. As shown, a profile can be symmetric or asymmetric. A profile <NUM> includes a central ridge with two valleys, a profile <NUM> includes a deep valley offset from center, a profile <NUM> include a flat valley bed with rounded walls, a profile <NUM> includes a flat valley bed with slanted walls, a profile <NUM> includes a semi-circular shape, a profile <NUM> includes a somewhat parabolic shape, a profile <NUM> includes a flat bed with a single slanted wall, a profile <NUM> includes two slanted portions with a straight portion, and a profile <NUM> includes a V-shape.

As to groove formation, groove or slot milling, keyslot milling, optionally followed by side milling, etc., may be utilized. As an example, a groove may be formed as a kerf using a cutting technique.

As an example, a groove can be of one or more profiles such as, for example, one or more of ellipsoidal, lenticular, polygonal (e.g., triangular, rectangular, etc.), circular, etc..

As an example, a groove can have a lenticular shaped opening, which may be represented on a curved surface such as the surface of a cylindrically shaped pin portion.

As an example, a groove can be volumetric. As an example, a groove can be defined by a surface such as, for example, a surface of a portion of a volumetric geometric body. For example, consider a spheroid, which may be prolate or oblate. As another example, consider a paraboloid. As an example, a volume of a groove may be represented by a portion of a lenticular body of rotation, where a lenticular shape may be defined by the intersection of two arcs (e.g., two circles, two ellipses, etc.).

As to a prolate spheroid, it can be a spheroid that is "pointy" instead of "squashed," i.e., one for which the polar radius c is greater than the equatorial radius a, so c > a (e.g., a spindle-shaped ellipsoid). A symmetrical egg can include the same shape at both ends and can approximate a prolate spheroid. A prolate spheroid is a surface of revolution obtained by rotating an ellipse about its major axis and has Cartesian equations: <MAT>.

As an example, a portion of a capsule shape can be formed where a capsule is a stadium of revolution that is a cylinder with two hemispherical caps on either end. As an example, a portion of a prolate spheroid with one or two conical ends may be formed.

As explained, a groove can be provided in a pin and/or a bearing where the groove extends an axial length with respect to a longitudinal axis of the pin (e.g., or an axis of an opening of a bearing, etc.). As an example, one or more grooves may be defined using a cylindrical coordinate system with a z-axis along a longitudinal axis of the pin. As an example, a groove can be defined in a separate coordinate system that can be for a corresponding shape (e.g., a geometric shape, etc.) that can be overlaid or intersected with a cylindrical coordinate system. For example, consider a lenticular body of revolution defined with respect to an axis of revolution where the lenticular body of revolution can be positioned with respect to a surface of a pin and/or a surface of a bearing represented in a cylindrical coordinate system such that a portion of the pin and/or a portion of the bearing can become a groove represented in part by a portion of the lenticular body of revolution.

As explained, an anti-rotation pin and an opening in a bearing can provide for various functions in a turbocharger. For example, consider positioning of a rotor group axially within a bore of a center housing, where the pin can transmit thrust load of a rotor group from the bearing (e.g., an outer race or journal) to a center housing, and where the pin can limit (e.g., resist) some amount of rotation of the bearing (e.g., an outer race or a journal). An undesirable function of an anti-rotation pin disposed at least in part in an opening of a bearing can be providing a transmission path for noise and vibration from a rotor group to a center housing.

In various types of turbochargers, during operation, an anti-rotation pin disposed at least in part in an opening of a bearing may be the only metal-to-metal connection between a rotor group and a center housing. As explained, during operation (e.g., sufficient lubricant pressure, etc.), an outer race can be supported in a bore of a center housing by a thin film of lubricant, which can be a squeeze film damper (SFD).

As explained, a pin and/or a bearing can be provided with one or more grooves that can be in fluid communication with a SFD such that the one or more grooves can receive lubricant. For example, consider a pin where axial groove features are added proximate to an end of the pin where some lubricant that is present in between the center housing and an outer race flows in the axial groove features to an interface area between the pin and the pin hole in the outer race (see, e.g., the opening <NUM> of the outer race <NUM>). In such an example, the presence of lubricant at this interface promotes a film of lubricant to form between the pin and the outer race that creates a damping element to reduce the vibration transmissibility from the outer race to the pin. As to a bearing, consider the bearing <NUM> of <FIG> where the surface <NUM> can be a surface that can form a lubricant film region with respect to a surface of a bore of a housing. As shown, the opening <NUM> is in the surface <NUM> such that lubricant can flow into one or more of the grooves <NUM>, <NUM>, <NUM> and <NUM>, for example, as shown via the regions <NUM>, <NUM>, <NUM> and <NUM> of <FIG>.

As explained, a groove feature (e.g., a groove) can be formed via one or more processes, which may include rolling and/or machining, which may be performed, for example, after turning. As explained, a process can involve removing material from a pin (see, e.g., <FIG>) and/or removing material from a bearing (see, e.g., <FIG>).

As to groove(s) position and/or length, these may be selected such that some amount of overlap occurs in a gap that exists between a bore wall of a center housing and an outer race where the groove(s) can extend axially into the interface between the outer race and the pin.

Referring again to <FIG>, a groove can be configured and a pin positioned such that the groove does not extend axially past the inner diameter of the outer race (see, e.g., <FIG>). Where additional flow of lubricant inwardly to a space defined by the inner diameter of the outer race is desired, a groove may extend past the inner diameter of the outer race; however, such an arrangement may aim to limit short circuiting of lubricant into a bearing assembly whereby lubricant flow via lubricant jets of the outer race are diminished to an extent that lubricant provided to rolling elements is insufficient. Where risk of short circuiting is to be eliminated, the ends of one or more grooves of a pin, in an assembled turbocharger assembly, can be short of an inner surface of an outer race (e.g., or journal) such that lubricant in a lubricant film region (see, e.g., the lubricant film region <NUM>) does not flow excessively through the one or more grooves and into a bearing assembly (e.g., an REB assembly).

As shown in the example of <FIG>, the grooves <NUM>, <NUM>, <NUM> and <NUM> do not extend to an inner surface <NUM> of the bearing <NUM>, which can help to reduce risk of short circuiting of lubricant, where it is desirable to reduce such risk. As explained, the wall <NUM> can extend from the surface <NUM> to the surface <NUM> and may be part of a cross-bore (e.g., cylinders with intersecting axes, etc.). Given the geometry, where a length of a groove on-axis is utilized for a groove off-axis, as the wall <NUM> can be thicker off-axis, the length may be assured to not be long enough for short circuiting, depending on the extent to which a pin extends into the opening <NUM> and overlaps the wall <NUM>.

As to parameters such as width of a groove, number of grooves, orientation of a groove or grooves, etc., these may be selected so as to preserve sufficient surface for contact between a pin and a surface of an outer race that defines an opening for the pin. For example, groove depth may be utilized for volume increase rather than groove width such that contact surface is sufficient. As contact surface decreases, the force experienced by particular surface regions of a pin can increase, which may cause some amount of wear to a pin, for example, at an edge of a groove. Where groove width is limited, contact may be more even such that edges of a groove are sufficiently close to experience a common level of force (e.g., stress, etc.). Where groove width is too wide, one edge may experience a level of force that differs from another edge, which may lead to higher force per unit area of one edge and a greater amount of wear.

As an example, a pin and/or a pin socket can include chamfers (bevels) that can forms a guide(s) for positioning and/or interference fitting, which may help to distribute force(s) more evenly around a circumference of an opening, which may allow compression to more occur gradually such that a pressing operation may be smoother, more easily controlled, etc. As an example, a shoulder about an opening of a bearing may include a chamfer or chamfers, which may provide for filling of lubricant that may flow to one or more grooves in a wall of the bearing that defines the opening.

As to thermal control, various materials expand when heated and shrink when cooled. As such, a pin may be cooled (e.g., and/or a housing may be heated depending on material, stress, etc.). As an example, a thermal control process may include heating and/or cooling of one or more components where at ambient temperature (e.g., and at operational temperatures of a turbocharger) compression results from thermal equilibrium of a pin in a pin socket. Such a process may be a shrink-fitting processor. As an example, a pin may be cooled using one or more agents (e.g., carbon dioxide at approximately -<NUM> degrees C, liquid nitrogen at approximately -<NUM> degrees C, etc.). In a sub-ambient temperature state (e.g., below approximately <NUM> degrees C), where a housing with a pin socket may be at least at an ambient temperature, a cooled pin may be positioned in the pin socket such that contact surfaces of the cooled pin and the pin socket contact each other to limit axial movement. In such a state, the pin and the housing may be held in such a position until the temperature of the pin rises such that the pin expands in diameter to create an interference fit.

As an example, a thermal process that involves cooling a pin may be more effective as to longevity of a turbocharger as heating for thermal expansion (e.g., above ambient temperature) may introduce one or more types of changes to material properties (e.g., tempering, etc.), may introduce undesirable stresses, etc..

As an example, a pin that is interference fit via a thermal process may be scar-less in that a contact surface of the pin does not translate or rotate against a contact surface of a pin socket in a manner that would scar the contact surface of the pin. In such an approach, one or more surfaces of a pin may be without scratches, etc., which may mean that debris is avoided, that a bearing with an aperture is located by a smoother portion of a pin in comparison to a scarred portion.

As an example, a pin may be made of a low alloy steel. As an example, a center housing may be made of cast iron (e.g., grey cast iron). As an example, a pin can be a machined component (e.g., formed from a stock cylinder of low alloy steel, etc.). As an example, a pin socket of a center housing can be formed via machining a cast center housing.

As an example, a pin can include an end socket, which may be of an M configuration (e.g., M4, etc.). As an example, where machining equipment for a center housing includes a tool or tools for threaded pin sockets, such a tool or tools may be sized according to the "M" configurations, which specify drill sizes. For example, consider a machining process for an M8 × <NUM> threaded socket that uses a <NUM> drill size. In such an example, a <NUM> diameter socket may be formed with a desired axial length where the <NUM> diameter socket may be tapped for forming threads or may be not tapped (non-tapped) such that it is threadless. Where a socket includes a <NUM> diameter portion, a pin can include a smaller diameter portion that steps to a larger diameter portion where the larger diameter portion has a diameter that exceeds <NUM> by approximately <NUM> to approximately <NUM> (e.g., <NUM>+ mm) for purposes of forming an interference fit upon contact of at least a portion of the <NUM> diameter portion of the socket of the housing and at least a portion of the <NUM>+ mm diameter portion of the pin. As an example, a diameter of a portion of a pin can be approximately <NUM> to approximately <NUM> larger than a portion of a pin socket or, for example, approximately <NUM> to approximately <NUM> larger than a portion of a pin socket for purposes of forming an interference fit.

As an example, a turbocharger assembly can include a housing that includes a bore defined by a bore wall and a pin socket that forms an opening in the bore wall; a bearing that includes a pin opening defined by a pin opening surface; a pin, where the pin includes a longitudinal pin axis and a pin surface; a groove in the pin opening surface or the pin surface, where the groove has an axial length; where, in a positioned state of bearing in the bore and the pin in the pin socket with part of the pin in the pin opening, a clearance exists between the bearing and the bore wall, where the groove is in fluid communication with the clearance to form a supply path for lubricant from the clearance to an interface between the pin surface and the pin opening surface.

As an example, a groove can be in a pin surface where an axial length of the groove overlaps at least a portion of a bearing-bore wall clearance and at least a portion of a pin opening surface in a bearing to form the supply path for lubricant from the clearance to an interface between the pin surface and the pin opening surface.

As an example, a bearing can be a rolling element bearing assembly (e.g., a REB assembly).

As an example, a bearing can include an outer race where a pin opening surface is a surface of the outer race (e.g., a wall surface that defines the pin opening, which can be, for example, a cross-bore that intersects a longitudinal bore of the outer race).

As an example, a bearing can be a journal bearing. A journal bearing can be a unitary component that is a unitary piece of material. A journal bearing can include one or more journal surfaces along a bore wall that form one or more corresponding lubricant film regions with respect to a rotatable shaft with one or more journal surfaces where the rotatable shaft is rotatably supported by the journal bearing in a housing (e.g., a center housing).

As an example, a bearing can be located using a pin disposed at least in part in a pin opening of the bearing where the pin may act to limit axial and/or rotational movements of the bearing while, for example, allowing for some amount of movement in a radial direction (e.g., a direction along a pin axis). Movement in a radial direction can provide for some changes in lubricant film thickness between an outer surface of the bearing and an inner surface of a bore of a housing.

As an example, a clearance between a bearing and a bore wall of a housing can define one or more lubricant film regions. For example, consider a lubricant film region that is adjacent to a pin opening of a bearing. As an example, a lubricant film region can be or can include a squeeze film damper region (e.g., that operates as a squeeze film damper (SFD)).

As an example, a pin surface of a pin can include a plurality of grooves and/or a pin opening surface of a bearing can include a plurality of grooves. As an example, a groove can be a groove in a pin surface and another groove can be a groove in a pin opening surface.

As an example, a turbocharge assembly, in a positioned state of a pin in a pin opening of a bearing, a groove can be aligned with a longitudinal axis of a bore of the housing that receives at least a portion of the bearing. In such an example, in the positioned state, the bearing can be translatable in a direction along the longitudinal axis to form a contact between the pin surface and the pin opening surface. As an example, in the positioned state, a groove may be oriented orthogonally to a longitudinal axis of the bore of the housing. In such an example, in the positioned state, a bearing can be rotatable clockwise or counter-clockwise to form a contact between the pin surface and the pin opening surface.

As an example, a groove can include a V-shaped profile in a plane, where a longitudinal pin axis of a pin (e.g., as received or receivable in a pin opening of a bearing) is normal to the plane. As an example, a pin surface of a pin can include a groove with a V-shaped profile and/or a pin opening surface of a pin opening of a bearing can include a groove with a V-shaped profile. As an example, where grooves exist in a pin surface and in a pin opening surface, groove profiles may differ or may be similar; noting that a pin groove can be from an outer cylindrical surface of a pin directed radially inward (into the pin) and a pin opening groove can be from a cylindrical surface of a bearing directed radially outward (into the bearing).

As an example, a groove can be a pin surface groove where a portion of an axial length of the groove overlaps with a pin socket of a housing (e.g., a center housing). As an example, a pin socket of a housing can be a cross-bore that intersects a through bore of the housing to form an opening a wall of the through bore of the housing where a pin can extend from the opening a distance into the through bore, for example, a distance sufficient for a portion of the pin to be received in a pin opening of a bearing disposed at least in part in the through bore of the housing.

As an example, a pin surface can include metal and a pin opening surface of a bearing can include metal. In such an example, in an operational state of the turbocharger assembly, the supply path for lubricant from the clearance to the interface between the pin surface and the pin opening surface supplies lubricant that damps energy at the interface generated by movement of the bearing.

As an example, a turbocharger assembly can include at least four grooves that are in fluid communication with an interface between a pin and a bearing (e.g., an interface defined by a pin surface and a pin opening surface) where movement of the bearing includes at least one of rotational movement and axial movement and where the pin limits such movement (e.g., to an amount less than approximately <NUM> degrees, to an amount less than approximately <NUM>, etc.).

As an example, a groove can be a pin surface groove of a pin where the pin includes a head portion that includes a marker for orientation of the groove in the bore of the housing. In such an example, the groove may be desirably aligned to address one or more issues such as one or more NVH issues. For example, where a turbocharger assembly is found to exhibit one or more NVH issues during operation, a pin may be oriented (e.g., rotated, etc.) to orient a groove where the groove can provide lubricant at an interface defined at least in part by a surface of the pin. Such an approach may address a particular NVH issue that arises at a particular operational condition (e.g., rotational speed of a turbocharger shaft, rotational speed of an internal combustion engine, etc.). As an example, a pin may include a plurality of grooves where the pin may be oriented in a manner that helps to mitigate one or more NVH issues. As explained, a marker can facilitate alignment and/or knowing what alignment helps to mitigate one or more NVH issues.

As an example, a groove can be a pin surface groove of a pin, where the pin includes an end surface and where the groove does not extend to the end surface.

As an example, a groove can be a pin surface groove of a pin, where a pin socket of a housing includes a mating region, where the pin includes a mating region to secure the pin in the pin socket with respect to the mating region of the pin socket, and where the groove is disposed in a region of the pin between the mating region and the end surface.

As an example, a method can include during operation of a turbocharger, flowing lubricant to a lubricant film region between a bearing and a bore wall of a housing, where a pin extends from an opening in the bore wall into a pin opening defined by a pin opening surface of the bearing, and where a groove exists at an interface between a pin surface of the pin and the pin opening surface of the bearing; and flowing at least a portion of the lubricant from the lubricant film region to the interface between the pin opening surface and the pin surface via the groove. Such a method can help to mitigate one or more issues such as, for example, one or more NVH issues that may occur during operation of the turbocharger assembly. As an example, in the foregoing example method, the at least a portion of the lubricant, at the interface, can damp energy generated by movement of the bearing. For example, a method can include damping energy generated by moving a bearing where moving the bearing occurs while operating an internal combustion engine and flowing exhaust to a turbocharger that includes the bearing.

According to further example which is not covered by the appended claims, there is provided a method comprising: during operation of a turbocharger, flowing lubricant to a lubricant film region between a bearing and a bore wall of a housing, wherein a pin extends from an opening in the bore wall into a pin opening defined by a pin opening surface of the bearing, and wherein a groove exists at an interface between a pin surface of the pin and the pin opening surface of the bearing; and flowing at least a portion of the lubricant from the lubricant film region to the interface between the pin opening surface and the pin surface via the groove. The at least a portion of the lubricant, at the interface, damps energy generated by movement of the bearing.

Claim 1:
A turbocharger assembly comprising:
a housing that comprises a bore (<NUM>) defined by a bore wall (<NUM>) and a pin socket (<NUM>) that forms an opening (<NUM>) in the bore wall;
a bearing that comprises a pin opening (<NUM>) defined by a pin opening surface (<NUM>);
a pin (<NUM>, <NUM>), wherein the pin comprises a longitudinal pin axis and a pin surface; and
a groove (<NUM>, <NUM>, <NUM>, <NUM>) in the pin surface, wherein the groove comprises an axial length;
wherein, in a positioned state of bearing in the bore and the pin in the pin socket with part of the pin in the pin opening, a clearance (<NUM>) exists between the bearing and the bore wall, wherein the groove is in fluid communication with the clearance to form a supply path for lubricant from the clearance to an interface between the pin surface and the pin opening surface, characterized in that the axial length of the groove overlaps at least a portion of the clearance and at least a portion of the pin opening surface to form the supply path for lubricant from the clearance to the interface between the pin surface and the pin opening surface.