Turbocharger ball bearing squeeze film damper

Abstract

A turbocharger, having a shaft coupled to a compressor wheel on a first end, and coupled to a turbine wheel on a second end; a center housing enveloping the shaft, having a first housing end proximate to the compressor wheel and a second housing end proximate to the turbine wheel; a compressor housing enveloping the compressor wheel and coupled with the center housing, having a compressor inlet and a compressor outlet; a turbine housing enveloping the turbine wheel and coupled with the center housing, having a turbine inlet and a turbine outlet; and a squeeze film damper disposed within the center housing disposed about the shaft and configured to center the shaft within the center housing, the squeeze film damper further including a cylindrical body; a cylindrical flange; a rib connecting the cylindrical body and the cylindrical flange; a bearing disposed within the cylindrical body.

Description

Turbocharger Ball Bearing Squeeze Film DamperCross-Reference to Related Applications

[0001] This application is an international patent application under the Patent Cooperation Treaty claiming priority to U.S. Provisional Patent Application Serial No. 63 / 650,109 filed on May 21, 2024.Technical Field

[0002] The present disclosure generally relates to turbochargers, and more specifically relates to bearings of turbochargers.Background

[0003] Turbochargers may be used in the automotive industry as power-adding components of automobile engines. Turbochargers may be generally provided with a shaft enveloped by a center housing with a compressor wheel and a turbine wheel at opposite ends of the shaft. The compressor wheel may be housed within a compressor housing with an inlet and an outlet, and the turbine wheel may be housed within a turbine housing having an inlet and an outlet.

[0004] In operation, hot exhaust gases from the engine attached to the turbocharger may enter the turbocharger through the inlet on the turbine housing, interact with blades of the turbine wheel, and exit the turbocharger through the outlet of the turbine housing. The exhaust gases may then be directed away from the engine and the turbocharger via an exhaust system. Interaction of the exhaust gas flow with the turbine wheel causes rotation of the turbine wheel, and thus rotates the shaft, which in turn rotates thecompressor wheel. Air may enter the inlet of the compressor housing, may be compressed by interaction with the compressor wheel, and may leave the turbocharger via the outlet of the compressor housing, where it may then be provided to the engine through an intake system.

[0005] Turbocharger components may spin at rotational speeds in the order of hundreds of thousands of re volutions per minute. Bearings are usually provided on each end of a turbocharger housing in order to center the shaft of the turbocharger and facilitate high rotational speed. Squeeze film dampers may be additionally provided between the bearings and the turbocharger housing in order to dampen radial forces from the shaft, and provide support flexibility . The squeeze film dampers are generally configured to float in a thin film of oil lubricating and move in a precessional manner. In order to do so, springs may be provided in the turbocharger housing to preload the bearing system in axial directions.

[0006] However, in the course of operation, biasing force from the spring at the turbine end, in addition to loading from aerodynamic force from the turbine, may provide loading onto the squeeze film damper at the compressor end. This loading may often be greater than a biasing force from the spring at the compressor end. In certain operating conditions, such as when lubricating oil within the turbocharger is cold, the loading and may cause a flange of the squeeze film damper to come in contact with the turbocharger housing and unintentionally become clamped. This clamping may prevent the squeeze film damper from precessing, and thus may transfer excess force, noise, and resonance through the turbocharger housing. Additionally, the clamping condition may influence the rotating components of the turbocharger, and may also affect oil flowto the bearing. In this manner, both the turbocharger housing and squeeze film damper may receive excess wear.

[0007] In light of the aforementioned shortcoming, there is a need for a turbocharger with an improved squeeze film damper.Summary of the Disclosure

[0008] In accordance with one aspect of the disclosure, a turbocharger may be provided. The turbocharger may include a compressor wheel, a turbine wheel, and a shaft connecting the compressor wheel and the turbine wheel. The turbocharger may include a housing enveloping the shaft, the compressor wheel, and the turbine wheel, the housing having a center section proximate the shaft. The turbocharger may include a squeeze film damper disposed within the center section about the shaft, and configured to center the shaft within the center section, the squeeze film damper including a cylindrical body, a cylindrical flange, a rib connecting the cylindrical body and the cylindrical flange, and a bearing disposed within the cylindrical body.

[0009] In accordance with another aspect of the disclosure, a squeeze film damper may be provided. The squeeze film damper may have a cylindrical body having a first end and a second end, and an outside surface and an inside surface. The squeeze film damper may have a cylindrical flange, and a rib extending from the second end of the cylindrical body to the cylindrical flange, the rib configured to connect the cylindrical body to the cylindrical flange and allow the cylindrical body to deflect relative to the cylindrical flange. The squeeze film damper may have a bearingdisposed within the cylindrical body, the bearing configured to surround a turbocharger shaft.

[0010] In accordance with yet another aspect of the disclosure, a method for assembling a turbocharger may be provided. The method may include providing a center housing, providing a shaft, and connecting a turbine wheel to the shaft. The method may include disposing a squeeze film damper within a cavity in the center housing, the squeeze film damper including a cylindrical body, a cylindrical flange, a rib connecting the cylindrical body and the cylindrical flange, and a bearing disposed within the cylindrical body. The method may include installing the shaft into the center housing and through the bearing of the squeeze film damper, and attaching a compressor wheel to the shaft at an opposite end to the turbine wheel. The method may include attaching a turbine housing to the center housing such that the turbine wheel is enveloped by the turbine housing, the turbine housing having a turbine inlet and a turbine outlet. The method may include attaching a compressor housing to the center housing such that the compressor wheel is enveloped by the compressor housing, the compressor housing having a compressor inlet and a compressor outlet.

[0011] These and other aspects and features of the present disclosure will be more readily understood when read in conjunction with the accompanying drawings.Brief Description of the Drawings

[0012] FIG. 1 is a cross-sectional view of a turbocharger constructed in accordance with the present disclosure.

[0013] FIG. 2 is an enlarged cross-sectional view of FIG. 1 showing the turbocharger in greater detail, constructed in accordance with the present disclosure.

[0014] FIG. 3 is a cross-sectional view of a squeeze film damper constructed in accordance with the present disclosure.

[0015] FIG. 4 is a perspective view of the squeeze film damper of FIG. 3, constructed in accordance with the present disclosure.

[0016] FIG. 5 is a flowchart depicting a sample sequence of steps which may be practiced in accordance with a method of assembling a turbocharger of the present disclosure.Detailed Description

[0017] Referring now to the drawings, and with specific reference to FIG. 1, a turbocharger is depicted and generally referred to using reference numeral 10. While the turbocharger 10 is depicted and described in conjunction with an automobile, such teachings can also find applicability with other machines such as trucks and power generators.

[0018] The turbocharger 10 is shown schematically in FIG. 1 . The turbocharger 10 may be formed of a compressor section 20, a turbine section 30, and a center housing 40.

[0019] The compressor section 20 may be formed from a compressor wheel 21 surrounded by a compressor housing 22. The compressor housing 22 may define a compressor inlet 23, from where ambient air may enter the turbocharger 10, and a compressor outlet 24, where compressed air may leave the compressor section 20, eventually routed to an air intake of an engine. The compressor housing 22 may be removably attached to the center housing 40. As shown in FIG. 1, the removable attachment may be formed by a compressor clamp 25, however, the compressorhousing 22 may be attached to the center housing 40 by other attachment means, such as bolts, screws, and the like.

[0020] Similarly, the turbine section 30 may be formed from a turbine wheel 31 surrounded by a turbine housing 32. The turbine housing 32 may define a turbine inlet 33, from where exhaust gas from the engine may re-enter the turbocharger 10 and drive the turbine wheel 31, and a turbine outlet 34, where the exhaust gas may leave the turbocharger 10. As with the compressor housing 22, the turbine housing 32 may be removably attached to the center housing 40. Again, as shown in FIG. 1, the removable attachment may be formed by a turbine clamp 35, however, the turbine housing 32 may also be attached to the center housing 40 by other attachment means, such as bolts, screws, and the like.

[0021] The center housing 40 of the turbocharger 10 may contain the critical rotating components of the turbocharger 10, as well as supporting members and lubrication elements. The center housing 40 of FIG. 1 is shown as divided into two components, a center housing body 41 w ith a center housing cover 42. As shown in FIG. 1, the center housing body 41 has a closed end proximate to the turbine section 30 and an open end proximate to the compressor section 20. As also shown in FIG. 1, the center housing cover 42 is mounted to the center housing body 41 at the open end, and is shown fastened with bolts 43, however, other fastening means as known may also be utilized.

[0022] A shaft 44 is contained within the center housing 40. The shaft 44 is connected to both the compressor wheel 21 and the turbine w heel 31. FIG. 1 illustrates this connection as having the turbine wheel 31 integral with the shaft 44. As shown in FIG. 1, once the shaft is inserted through the center housing 40, thecompressor wheel 21 is fitted on the opposite end of the shaft 44 and is secured by a nut 45. Other connections between the shaft 44. compressor wheel 21, and turbine wheel 31 as known may be utilized as well.

[0023] The turbocharger 10 may be an electric turbocharger. Where the turbocharger 10 is an electric turbocharger, or “eTurbo,'’ the turbocharger 10 may include a stator 46 mounted stationary within the center housing 40, and a rotor 47 attached to the shaft 44. As the shaft 44 and rotor 47, changes to a magnetic field between the rotor 47 and the stator 46 cause electrical current to be generated by the turbocharger 10. Similarly, electrical current may be applied to the turbocharger 10 in a reverse direction such that the stator 46 causes the rotor 47, and thus the shaft 44 to begin to rotate. In certain operating conditions of the turbocharger 10 where air flow to the turbine wheel 31 is low, this configuration may be desirable to increase efficiency.

[0024] The center housing 40 may include a lubrication system in order to deliver oil to the rotating components of the turbocharger 10. Oil passages 48 may be provided in the center housing 40 to precisely deliver oil to certain components. In order to contain the lubricating oil within the center housing 40, a seal 49 may be provided about the shaft 44.

[0025] As the shaft 44, may rotate on an order of magnitude of hundreds of thousands of rotations per minute, support structures are required to precisely locate the shaft 44 on an axis of rotation. In the turbocharger of FIG. 1, this support structure is accomplished in the form of a squeeze film damper 50. The squeeze film damper 50 may be provided in more than one location within the center housing 40.As depicted in FIG. 1, one of the squeeze film damper 50 is disposed within a cavityin the center housing body 41, and another of the squeeze film damper 50 is disposed within a second cavity in the center housing cover 42.

[0026] The squeeze film damper 50 disposed within the center housing cover 42 is shown in greater detail in FIGS. 2-4. The squeeze film damper 50 of FIGS. 2-4 may be identical to other of the squeeze film damper 50 located in the center housing body 41 , as shown in FIG. 1.

[0027] The squeeze film damper 50 may be formed of a cylindrical body 51 having a first end 52, a second end 53, an outside surface 54, and an inside surface 55. The squeeze film damper 50 may include a bearing disposed within the cylindrical body 51. As depicted in FIGS. 2-4, the cylindrical body 51 is integral with the bearing, and the cylindrical body 51 forms an outer race of the bearing having a bearing groove 56 for locating balls 60 within a cage 61, and having an inner race 59 surrounding and in contact with the shaft 44. How ever, the bearing may be a separate component from the cylindrical body 51, and may be fitted within the cylindrical body 51 as known. The bearing is also depicted as a ball bearing, how ever, other bearings as known may also be utilized.

[0028] In order to locate the squeeze film damper 50 within the center housing cover 42, a cylindrical flange 57 may be provided, with a rib 58 extending from the second end 53 of the cylindrical body 51 to the cylindrical flange 57. In the embodiment of FIGS. 2-4, eight of the rib 58 are provided, connecting the cylindrical body 51 to the cylindrical flange 57. The rib 58 is shown in FIG. 4 as having a parallelogram cross section, although other cross sections as known may be utilized. The rib 58 allows the cylindrical body 51 to deflect relative to the cylindrical flange 57 such that, if the cylindrical flange 57 is clamped, the cylindrical body 51 may stillbe permitted to move. The cylindrical flange 57 may also include a notch 65 for disposing the squeeze film damper 50 within the center housing cover 42 in a specific orientation.

[0029] As shown in FIG. 2, the oil passages 48 in the center housing 40 may deliver lubricating oil to the squeeze film damper 50. The lubricating oil may be disposed on the outside surface 54 of the squeeze film damper 50 such that the squeeze film damper 50 floats within the center housing cover 42. In order to maintain the oil film, and contain the oil within a specific location on the outside surface 54, a groove 62 may be provided on the outside surface 54 of the squeeze film damper 50 at the first end 52. The groove 62 may be configured to receive an o-ring 63. The o-ring 63 contacts the center housing cover 42, and maintains the oil film on the outside surface 54. The squeeze film damper 50 may also include an oil jet 64, shown in FIG. 3, configured to provide lubricating oil from the outside surface 54 of the cylindrical body 51 to the inside surface 55 and directed to the balls 60 of the bearing.

[0030] As depicted in FIG. 1, a first preload spring 70 and a second preload spring 80 are disposed within the center housing 40 in order to bias the squeeze film damper 50 proximate the compressor section 20, and the squeeze film damper 50 proximate the turbine section 30, respectively. The first preload spring 70 and the squeeze film damper 50 proximate the compressor section 20 are shown in greater detail in FIG. 2. The first preload spring 70 is located in the center housing cover 42 and orientated to provide an axial force on the squeeze film damper 50 in a direction away from the compressor wheel 21. Similarly, the second preload spring 80 is located in the center housing body 41 and orientated to provide an axial force on the squeeze film damper 50 in a direction away from the turbine w heel 31.Industrial Applicability

[0031] In operation, the teachings of the present disclosure can find applicability in many industries including but not limited to power generation, automotive, on and off highway trucking, mining, and construction industries. While depicted and described in conjunction with an automobile, such teachings can also find applicability with other machines that utilize turbocharger technology such as power generators, on and off trucks, and work machines as well.

[0032] FIG. 5 illustrates a visual representation of a method of assembling the turbocharger 10 of the present disclosure. In a first step 101, the center housing 40 is provided. The center housing 40 may include the center housing body 41 and the center housing cover 42 disassembled, and may include the stator 46 disposed within. In a second step 102, the shaft 44 and the turbine wheel 31 may be connected. As shown in FIG. 1 , the shaft 44 may be integral with the turbine wheel 31.

[0033] In a third step 103, the first preload spring 70 and the second preload spring 80 may be disposed within the center housing cover 42 and the center housing body 41. As one of the squeeze film damper 50 is installed over each of the first preload spring 70 and the second preload spring 80 and within the center housing cover 42 and the center housing body 41 in a fourth step 104, a preload is applied to the squeeze film damper in an axial direction.

[0034] In a fifth step 105, the shaft 44 is inserted through the center housing body 41 and the squeeze film damper 50 disposed therein. The inner race 59 of the bearing of the squeeze film damper 50 is disposed about the shaft 44. The rotor 47 is then disposed about the shaft 44 proximate the stator 46. The shaft 44 is also insertedthrough the center housing cover 42 and the squeeze film damper 50 disposed therein, and the center housing cover 42 is attached the center housing body 41 with bolts 43.

[0035] The compressor wheel 21 is then fitted to the shaft 44. in a sixth step 106, at an end of the shaft 44 opposite to that of the turbine wheel 31. As shown in FIG. 1, the compressor wheel 21 is secured with the nut 45. In a seventh step 107, the turbine housing 32 is attached to the center housing 40 with the turbine clamp 35 such that the turbine wheel 31 is enveloped by the turbine housing 32. Similarly, in a final step 108, the compressor housing 22 is attached to the center housing 40 with the compressor clamp 25 such that the compressor wheel 21 is enveloped by the compressor housing 22.

[0036] The method 100 of assembling the turbocharger 10 describes how proper installation of the squeeze film damper 50 provides for proper location and preloading of the squeeze film damper 50. Utilizing the squeeze film damper 50 having the rib 58 connecting the cylindrical body 51 with the cylindrical flange 57 allows for proper precessional motion of the squeeze film damper 50 even if excess clamping force is provided. This improvement allow s for reduced w arranty costs, increased bearing life, improved noise, vibration, and harshness from the turbocharger 10, improved imbalance problems, and improved piston ring wear in an engine connected to the turbocharger 10.

[0037] While the squeeze film damper 50 is described in conjunction with the shaft 44 of the turbocharger 10, the squeeze film damper 50 may be adapted to be used in various forms of machinery utilizing rotating elements. The rib 58 of the squeeze film damper 50 is configured to dampen the shaft 44 and may prevent any rotatingelements from precessing excessively and generating unwanted noise, vibrations, and / or heat.

[0038] It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.

Claims

ClaimsWhat is claimed is:

1. A turbocharger, comprising: a compressor wheel; a turbine wheel; a shaft connecting the compressor wheel and the turbine wheel; a housing enveloping the shaft, the compressor wheel and the turbine wheel, the housing having a center section proximate the shaft; and a squeeze film damper disposed within the center section about the shaft, and configured to center the shaft within the center section, the squeeze film damper including a cylindrical body, a cylindrical flange, a rib connecting the cylindrical body and the cylindrical flange, and a bearing disposed within the cylindrical body.

2. The turbocharger of claim 1, wherein the turbocharger is an electric turbocharger, and further comprises a stator contained in the center section and a rotor disposed on the shaft.

3. The turbocharger of claim 1, further comprising a preload spring disposed between the squeeze film damper and the center section, configured to provide an axial force relative to the shaft.

4. The turbocharger of claim 3, further comprising a first preload spring and a first squeeze film damper disposed in the center section proximate the compressor wheel, the first preload spring providing the axial force on the first squeeze film damper away from the compressor wheel; and a second preload spring and a second squeeze film damper disposed in the center section proximate the turbine wheel, the second preload spring providing the axial force on the second squeeze film damper away from the turbine wheel.

5. The turbocharger of claim 1, further comprising an oil passage w ithin the center section configured to deliver oil between the squeeze film damper and the center section.

6. The turbocharger of claim 5, further comprising an oil j et through the cylindrical body of the squeeze film damper, the oil jet configured to provide lubricating oil from an outside surface of the cylindrical body to an inside surface of the cylindrical body and directed to the bearing.

7. The turbocharger of claim 6, further comprising a groove on the outside surface of the cylindrical body of the squeeze film damper proximate to the oil jet, the groove configured to receive an o-ring.

8. A squeeze film damper, comprising: a cylindrical body having a first end and a second end, and an outside surface and an inside surface;a cylindrical flange; a rib extending from the second end of the cylindrical body to the cylindrical flange; the rib configured to connect the cylindrical body to the cylindrical flange and allow the cylindrical body to deflect relative to the cylindrical flange; and a bearing disposed within the cylindrical body, the bearing configured to surround a turbocharger shaft.

9. The squeeze film damper of claim 8, wherein the rib further comprises a plurality of ribs.

10. The squeeze film damper of claim 8, wherein the cylindrical flange includes a notch for disposing the squeeze film damper in a specific orientation.

11. The squeeze film damper of claim 8, further comprising a groove on the outside surface of the cylindrical body proximate to the first end, the groove configured to receive an o-ring.

12. The squeeze film damper of claim 8, further comprising an oil jet through the cylindrical body, the oil jet configured to provide lubricating oil from the outside surface of the cylindrical body to the inside surface of the cylindrical body and directed to the bearing.

13. The squeeze film damper of claim 8, wherein the bearing is pressed into the cylindrical body, and an outer race of the bearing is in contact with the inside surface of the cylindrical body.

14. The squeeze film damper of claim 8, wherein the cylindrical body further comprises an outside race of the bearing, and the bearing is integral with the cylindrical body.

15. A method for assembling a turbocharger, comprising: providing a center housing; providing a shaft; connecting a turbine wheel to the shaft; disposing a squeeze film damper within a cavity in the center housing, the squeeze film damper including a cylindrical body, a cylindrical flange, a rib connecting the cylindrical body and the cylindrical flange, and a bearing disposed within the cylindrical body; installing the shaft into the center housing and through the bearing of the squeeze film damper; attaching a compressor wheel to the shaft at an opposite end to the turbine wheel; attaching a turbine housing to the center housing such that the turbine wheel is enveloped by the turbine housing, the turbine housing having a turbine inlet and a turbine outlet; andataching a compressor housing to the center housing such that the compressor wheel is enveloped by the compressor housing, the compressor housing having a compressor inlet and a compressor outlet.

16. The method of claim 15, prior to the step of disposing the squeeze film damper within the cavity in the center housing, further comprising disposing a spring in the cavity such that when the squeeze film damper is disposed in the canty, the spring providing a preload in an axial direction relative to the shaft.

17. The method of claim 15, wherein the step of providing the center housing further comprises providing the center housing with a center housing bodyhaving a closed end and an open end, and a center housing cover configured to cover the open end.

18. The method of claim 17, wherein the step of disposing the squeeze film damper further comprises: disposing a first squeeze film damper within a first cavity in the center housing body proximate the closed end; and disposing a second squeeze film damper within a second cavity in the center housing cover.

19. The method of claim 18, further comprising: prior to disposing the first squeeze film damper, disposing a first spring in the first cavity such that the first spring provides a preload in an axial direction away from the first cavity; andprior to disposing the second squeeze film damper, disposing a second spring in the second cavity such that the second spring provides a preload in an axial direction away from the second cavity.

20. The method of claim 18, wherein the step of installing the shaft into the center housing further comprises: installing the shaft through the first squeeze film damper; installing the shaft through the second squeeze film damper; and attaching the center housing cover to the open end of the center housing body.

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