Single row ball bearing with integral squeeze film damper

Abstract

To provide a rolling element bearing assembly that may be used in an electrically assisted turbocharger.SOLUTION: A bearing assembly 100 includes an inner race 110 having an outer diameter 112 defining an inner raceway 114, an outer race 120 having an outer diameter 122 and an inner diameter 124, the outer-race inner diameter 124 defining an outer raceway 126, a single row of rolling elements 130 between the inner raceway and the outer raceway, and a squeeze-film damper 140 integrated with the outer race to form a single component. The squeeze-film damper provides a squeeze-film damper surface 144 between the outer-race outer diameter and a housing.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates generally to bearings, and more particularly to methods and apparatus for manufacturing bearings and bearing components for use in rotating machines. [Background technology]

[0002] Rolling element bearings are frequently used in machines and equipment having rotating parts. A typical rolling element bearing includes an inner race and an outer race with balls or rollers disposed between the races.

[0003] High speed equipment such as turbochargers, compressor turbines and gas turbines use rolling element bearings around a rotating shaft. In particular, turbochargers are used to improve the performance of internal combustion engines. Some turbochargers utilize exhaust gases for power, while others may operate with an electric motor operatively coupled to the shaft, either alone or assisted by the exhaust gases to power the turbocharger.

[0004] Turbochargers can rotate at speeds in excess of 100,000 rpm. Many improvements have been made to improve their performance and lifespan, especially in relation to lubrication issues. For example, some turbocharger bearings incorporate damping characteristics to dampen vibrations, allowing the device to obtain safe operating speeds as it accelerates through the resonance region. Additionally, damped bearings help damp small vibrations caused by imbalances when the machine is operating under normal conditions or at normal operating speeds.

[0005] U.S. Patent No. 5,425,584 discloses a fluid damped support for a rolling element bearing. In the '584 patent, a network of closely spaced beams supports the outer ring of a roller bearing from movement in any direction. Liquid is supplied to the spaces between the beams to dampen the movement. The structure and spacing between the beams are designed to provide damping characteristics. However, there remains a need for systems and methods to reduce part count, provide easy assembly, and reduce tolerance stack-up of multiple components. Thus, there is a need for a single row ball bearing with an integral squeeze-film damper. Summary of the Invention [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a rolling element bearing assembly is disclosed. The rolling element bearing assembly may be used in an electrically assisted turbocharger. The bearing assembly includes an inner ring having an outer diameter defining an inner raceway, an outer ring having an outer diameter and an inner diameter, the inner diameter of the outer ring defining an outer raceway, a single row of rolling elements between the inner raceway and the outer raceway, and a squeeze film damper integrated with the outer ring to form a single component. The squeeze film damper provides a squeeze film damper surface between the outer ring outer diameter and a housing.

[0007] In one such embodiment, the bearing assembly further includes an oil jet in the outer ring. In another such embodiment, the bearing assembly includes an end-stop flange matable with the outer ring and configured to engage with the housing. In such an embodiment, the end-stop flange is rotationally restrained relative to the outer ring and further includes an anti-rotation feature configured to engage with the housing. In one such embodiment, the end-stop flange is attached to the outer ring via a snap ring.

[0008] In another embodiment, the bearing assembly includes an end stop flange integral with the outer ring and configured to engage the housing. In one such embodiment, the end stop flange further includes an anti-rotation feature configured to engage the housing.

[0009] Another embodiment takes the form of an electrically assisted turbocharger including a housing, a turbine wheel, a compressor wheel, a shaft supported within the housing and interconnecting the turbine wheel and the compressor wheel, an electric motor disposed within the housing and operably coupled to the shaft, and at least one rolling element bearing assembly surrounding the shaft, the at least one rolling element bearing assembly including an inner ring, an outer ring, a plurality of rolling elements between the inner ring and the outer ring, and a squeeze film damper integrated into the outer ring to provide a squeeze film damper surface between an outer diameter of the outer ring and the housing.

[0010] In one such embodiment, the turbocharger further includes an oil jet in the outer ring. In another such embodiment, the turbocharger further includes an end stop flange matable with the outer ring and configured to engage the housing. In such an embodiment, the end stop flange further includes an anti-rotation feature that is rotationally constrained relative to the outer ring and configured to engage the housing. In one such embodiment, the end stop flange is attached to the outer ring via a snap ring.

[0011] In another such embodiment, the turbocharger further includes an end stop flange integral with the outer ring and configured to engage the housing. The end stop flange may further include a pin opening configured to engage the anti-rotation pin.

[0012] Another embodiment takes the form of an electrically assisted turbocharger including a housing, a turbine wheel, a compressor wheel, a shaft supported within the housing and interconnecting the turbine wheel and the compressor wheel, an electric motor disposed within the housing and operably coupled to the shaft, a turbine side rolling element bearing disposed about the turbine side shaft of the electric motor, and a compressor side rolling element bearing disposed about the compressor side shaft of the electric motor.

[0013] At least one or both of the turbine side rolling element bearing and the compressor side rolling element bearing include an inner ring having an outer diameter defining an inner raceway, an outer diameter defining an outer raceway, an outer ring having an inner diameter, an oil jet configured to provide lubrication to the inner raceway, a single row of rolling elements between the inner raceway and the outer raceway, and a squeeze film damper integrated with the outer ring to form a single component. The squeeze film damper provides a squeeze film damper surface between the outer ring outer diameter and a housing. An end stop flange is mateable with the outer ring and is attached to the outer ring with a snap ring. The end stop flange is rotationally restrained relative to the outer ring and further engages an anti-rotation feature on the housing.

[0014] Another embodiment takes the form of an electrically driven compressor including a housing, at least one compressor wheel, a shaft supported within the housing and interconnected with the at least one compressor wheel, an electric motor disposed within the housing and operatively coupled to the shaft, and at least one compressor rolling element bearing disposed about the shaft on the compressor side of the electric motor. In such an embodiment, the compressor side rolling element bearing includes an inner ring having an outer diameter defining an inner raceway, an outer ring having an outer diameter and an inner diameter, and an oil jet configured to provide lubrication to the inner raceway, the outer ring inner diameter defining an outer raceway, a single row of rolling elements between the inner raceway and the outer raceway, a squeeze film damper integrated with the outer ring to form a single component, the squeeze film damper providing a squeeze film damper surface between the outer ring outer diameter and the housing, and an end-stop flange matable with the outer ring and attached to the outer ring with a snap ring. The end stop flange is rotationally restrained relative to the outer race and further engages an anti-rotation feature on the housing.

[0015] 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]

[0016] [Figure 1] FIG. 1 shows a cross-sectional view of a conventional turbocharger bearing assembly. [Diagram 2] FIG. 2 illustrates a cross-sectional view of a first bearing assembly according to one embodiment of the present disclosure. [Diagram 3] FIG. 3 shows a perspective view of an outer ring according to one embodiment of the present disclosure. [Figure 4] FIG. 4 illustrates a perspective view of an inner race according to one embodiment of the present disclosure. [Diagram 5] FIG. 5 illustrates a perspective view of an end stop flange according to one embodiment of the present disclosure. [Figure 6]FIG. 6 illustrates a perspective view of a snap ring according to one embodiment of the present disclosure. [Figure 7] FIG. 7 illustrates a cross-sectional view of a bearing assembly installed in a turbocharger according to one embodiment of the disclosure. [Figure 8] FIG. 8 illustrates a cross-sectional view of a second bearing assembly according to one embodiment of the present disclosure. [Figure 9] FIG. 9 illustrates a cross-sectional view of a turbocharger according to one embodiment of the present disclosure. [Figure 10] FIG. 10 illustrates a motorized compressor having a bearing assembly according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Turning now to the drawings, Figure 1 illustrates a cross-sectional view of a conventional turbocharger bearing assembly. In particular, Figure 1 illustrates a cross-sectional view 50 of a conventional turbocharger with rolling element bearings. In the cross-sectional views included herein, several components are shown on both the top and bottom of the view. For example, a ring-like outer race surrounds the shaft, but appears both above and below the centerline in a cross section taken along the centerline. Throughout this disclosure, such components are not illustrated and shown on both halves of the centerline for clarity.

[0018] In cross-sectional view 50, shaft 10 is shown supported by a bearing. The bearing is received within a housing 15 and includes an inner ring 11 having an inner raceway 12 along the inner ring outer diameter, and an outer ring 13 having an outer raceway 14 along the outer ring inner diameter. Rolling elements 21 are disposed between the raceways 12, 24 of the inner ring 11 and outer ring 13.

[0019] The bearing cup 18 interfaces with the outer ring 13 via a tight clearance fit, interference fit, or the like to form a rigid connection between the outer ring 13 and the bearing cup 18. In some embodiments, the inner and outer rings are press fit into the bearing cup 18. The bearing cup 18 further includes an axial end stop 19 that interfaces with a portion of the housing 15 to limit translational movement of the bearing along the longitudinal axis CL along the centerline of the shaft 10. The bearing further includes an oil deflector 20 that is used to direct oil throughout the bearing.

[0020] A squeeze film damper surface 16 is formed between the bearing cup 18 and the housing 15. The squeeze film damper surface 16 includes a gap having a dimension tuned to optimize the oil film thickness and, therefore, the damping characteristics of the bearing assembly. Optimizing the gap dimension for the squeeze film damper surface 16 can be difficult in conventional designs of rolling element bearings as a result of the multiple components each having manufacturing tolerances.

[0021] FIG. 2 illustrates a cross-sectional view of a first bearing assembly according to an embodiment of the present disclosure. In particular, FIG. 2 illustrates a diagram of a bearing assembly 100. The bearing assembly 100 may be used in any applicable rotating machine. Exemplary machines include turbochargers, electric turbochargers (e.g., eTurbos), electrically assisted turbochargers, gas turbines, and the like. The bearing assembly 100 includes an inner ring 110 (shown separated from the other bearing assembly components in FIG. 4 ) having an outer diameter 112 that defines an inner raceway 114, and an outer ring 120 (shown separated from the other bearing assembly components in FIG. 3 ) having both an outer diameter 122 and an inner diameter 124, the outer ring inner diameter 124 defining an outer raceway 126.

[0022] A single row of rolling elements 130 are disposed between the inner raceway 114 and the outer raceway 126. The rolling elements 130 are fitted between the raceways 114, 126 and are appropriately sized to provide a firm metal-to-metal contact between the inner and outer raceways 110, 120. A squeeze film damper 140 is integrated into the outer raceway 120 to form a single component. The squeeze film damper 140 provides a squeeze film damper surface 144 between the outer raceway OD 122 and a housing 142 (not shown in FIG. 1). The squeeze film damper surface 144 provides an adequate clearance between the squeeze film damper 140 and the housing 142 to adequately damp vibrations experienced by the bearing assembly.

[0023] In one embodiment, the bearing assembly 100 further includes an oil jet 202 in the outer ring 120. The oil jet 202 provides a flow of oil from the inner diameter 124 of the outer ring 120 to the outer diameter 122 of the outer ring 120. The oil jet 202 is a feature of the injection mold of the outer ring 120, and may be formed in the outer ring 120 in any number of ways, including machining or drilling the outer ring 120, etc. Additionally, the location of the oil jet 202 may be located at various locations along the outer ring. For example, the oil jet 202 may be located at either an upper or lower location of the outer ring 120.

[0024] The outer ring 120 may include multiple oil jets 202 circumferentially disposed around the circumference of the outer ring 120. For example, three oil jets 202 may be disposed around the circumference of the outer ring 120, spaced 120° apart from one another. However, any number of oil jets 202 may be used.

[0025] In one embodiment, the bearing assembly 100 further includes an end-stop flange 302 (shown separated from other bearing assembly components in FIG. 5 ) that can mate with the outer ring 120. The end-stop flange 302 is configured to engage or abut the housing 142. The end-stop flange 302 can include a tab 342 configured to be inserted into a slot 340 on the outer ring 120. Inserting the tab 342 into the slot 340 maintains rotational alignment about the axis CL between the outer ring 120 and the end-stop flange 302 (e.g., rotationally constrains the outer ring 120 to the end-stop flange 302). In another embodiment, the end-stop flange further includes an anti-rotation feature 304 configured to engage with the housing 142. For example, the anti-rotation feature 304 can include a pin opening configured to receive an anti-rotation pin on the housing. When an anti-rotation pin (not shown) is inserted into the anti-rotation feature 304, the end-stop flange 302 is rotationally constrained relative to the housing 142.

[0026] Some embodiments combine an endstop flange 302 having both a tab 342 and a slot 340 with an anti-rotation feature 304. In such embodiments, when the anti-rotation feature 304 engages the endstop flange 302, both the outer ring 120 and the endstop flange 302 are prevented from rotating about the CL axis, in part, by the anti-rotation feature of the outer ring 120 engaging the housing 142, and the tab 342 of the endstop flange 302 seating in the slot 340 of the outer ring 120. In various embodiments, engaging the anti-rotation feature 304 includes inserting an anti-rotation pin of the housing into the anti-rotation feature 304.

[0027] Bearing assembly 100 is also shown to have a snap ring 306. Snap ring 306 is sized to fit within groove 308 to limit translation of end stop flange 302 along axis CL.

[0028] Figure 3 illustrates a perspective view of an outer ring according to one embodiment of the present disclosure. The outer ring 120 illustrated in Figure 3 more clearly illustrates the aspects of the outer ring 120 illustrated in Figure 2. In particular, the outer ring 120 in Figure 3 illustrates a slot 340 configured to align with a tab 342 on the end stop flange 302.

[0029] Also shown is an oil jet 202 that extends from the outer periphery of the outer ring 120 to the inner periphery of the outer ring 120 .

[0030] 4 shows a perspective view of an inner race according to one embodiment of the present disclosure. The inner race 110 shown in FIG. 4 more clearly illustrates the aspects of the inner race shown in FIG.

[0031] FIG. 5 illustrates a perspective view of an endstop flange according to one embodiment of the present disclosure. The endstop flange 302 illustrated in FIG. 5 more clearly illustrates the aspect of the endstop flange illustrated in FIG. 2. In particular, the endstop flange 302 includes an anti-rotation feature 304 disposed along the circumference of the endstop flange 302. As shown, the anti-rotation feature 304 is realized as two apertures disposed on opposite sides along the circumference of the endstop flange 302. In some embodiments, a different number of apertures are disposed along the circumference of the endstop flange 302. The endstop flange 302 in FIG. 5 also illustrates a tab 342 that is aligned with the slot 340. It should be noted that the tab 342 and the slot 340 can be switched positions, with the slot being disposed on the endstop flange 302 and the tab 342 being disposed on the outer ring 120.

[0032] 6 shows a perspective view of a snap ring according to one embodiment of the present disclosure. The snap ring 306 is shown as circular with an expansion break at the top, and an eye hole 310 is located proximate to the expansion break.

[0033] Figure 7 illustrates a cross-sectional view of a bearing assembly installed in a turbocharger according to one embodiment of the present disclosure. In particular, Figure 7 illustrates a cross-sectional view of the bearing assembly shown in Figure 2. As shown in Figure 7, end stop flange 302 is attached to outer ring 120 via snap ring 306. Snap ring 306 (shown separated from the other bearing assembly components in Figure 6) is sized to fit within groove 802 on outer ring 120.

[0034] Mounting the end stop flange 302 and the snap ring 306 on the outer ring 120 can be accomplished by aligning the tab 342 of the end stop flange 302 with the slot 340 of the outer ring 120, so that the outer ring 120 abuts the end stop flange 302 at a contact point 804. The snap ring 306 can be expanded by prying apart the eye hole 310. The snap ring 306 can then be placed in the groove 802 of the end stop flange 302. The snap ring 306 can then be restored to a nominal geometric shape by returning the eye hole 310 to a nominal position without prying apart. The snap ring 306 is thus restrained in the groove 802. Furthermore, the end stop flange 302 is restricted from translating along the axis CL at the contact point 804 on the outer ring 120 on one side, and by the snap ring 306 on the other side.

[0035] Figure 8 illustrates a cross-sectional view of a second bearing assembly according to one embodiment of the present disclosure. In particular, Figure 8 illustrates a bearing assembly 800 installed in a housing 142 and includes many of the same components as the bearing assemblies illustrated in Figures 2 and 7. However, in Figure 8, the end stop flange 404 is integrated with the outer ring 120 to form a single component 420. This is as opposed to Figures 2 and 7, in which the outer ring and end stop flange are separate components.

[0036] As such, end stop flange 404 may include similar components as end stop flange 302. In one such embodiment, end stop flange 404 includes an anti-rotation feature (e.g., such as anti-rotation feature 304) configured to engage with housing 142. Thus, when the anti-rotation feature (e.g., 304) engages housing 142, integral outer ring 120 and end stop flange 404 are rotationally constrained together as a single component 420 with housing 142. [Industrial Applicability]

[0037] In general, the teachings of the present disclosure may find broad applicability in many industries, including, but not limited to, the automotive, single-track, marine, electronic, and transportation industries. In particular, the present disclosure may find applicability in any industry that uses machines or equipment that include rotating components. Disclosed herein are various non-limiting examples of machines that may include the rolling element bearing assemblies of the present disclosure.

[0038] Figure 9 illustrates a cross-sectional view of a turbocharger according to one embodiment of the present disclosure. In particular, Figure 9 illustrates an electrically assisted turbocharger 900. The turbocharger 900 includes a housing 901, a turbine wheel 902, a compressor wheel 903, a shaft 904 supported within the housing 901 and interconnecting the turbine wheel 902 and the compressor wheel 903, an electric motor 905 disposed within the housing 901 and operably coupled to the shaft 904, an oil supply system 906, and at least one rolling element bearing assembly 907 supporting the shaft 904.

[0039] In such an embodiment, the electric motor 905 is disposed between a first end (e.g., a left turbine end) and a second end (e.g., a right compressor end). In this manner, multiple bearing assemblies 907 may be used to support the shaft 904 on each side of the electric motor 905. Here, bearing assembly 907-1 is shown on the turbine side of the electric motor 905 and bearing assembly 907-2 is shown on the compressor side of the electric motor 905.

[0040] An electric motor 905 can be operatively coupled to the shaft 904 to provide a rotational force to the shaft 904, thus driving the rotation of the turbine and compressor wheels 902, 903 in a variety of manners. For example, the electric motor 905 can be mounted on the outside of the turbocharger 900 and coupled to the nose of the compressor wheel via a splined coupler. The electric motor 905 can further act on the shaft via magnetic forces to provide the desired rotational effect.

[0041] At least one rolling element bearing assembly 907-1, 907-2 may be realized by bearing assembly 100 shown in Figures 2 and 7, or by bearing assembly 800 shown in Figure 8. Thus, the bearing assembly includes an inner ring 110, an outer ring 120, a plurality of rolling elements 130 between the inner ring 110 and the outer ring 120, and a squeeze film damper 140 integrated into the outer ring 120 to provide a squeeze film damper surface 144 between the outer diameter 122 of the outer ring 120 and the housing 901.

[0042] In one such embodiment, the bearing assemblies 907 - 1 , 907 - 2 of the turbocharger 900 further include oil jets 202 within the outer ring 120 that are fluidly connected to the oil supply system 906 .

[0043] FIG. 10 illustrates an electric compressor having a bearing assembly according to one embodiment of the present disclosure. In particular, FIG. 10 illustrates a compressor 1000 including a housing 1001, a compressor wheel 1003 operably coupled to a shaft 1004, an electric motor 1005 operably coupled to the shaft, and bearing assemblies 1007-1 and 1007-2. Here, similar to turbocharger 900, one or both of bearing assemblies 1007-1, 1007-2 may be realized by any of the bearing assemblies 100 or 800 disclosed herein. However, unlike turbocharger 900, compressor 1000 does not include a turbine wheel, but includes compressor wheel 1003 at one end. Thus, shaft 1004 is actuated by electric motor 1005, and bearing assemblies 1007-1, 1007-2 are disposed on either side of electric motor 1005. Bearing assembly 1007-1 (e.g., a compressor side bearing assembly) is located on the compressor side of the electric motor 1005, and bearing assembly 1007-2 (e.g., a second bearing assembly) is located on the side of the electric motor 1005 opposite the compressor wheel 1003.

[0044] In another embodiment, a two-stage electric compressor can utilize the bearing assemblies disclosed herein. Such a machine can be similar to turbocharger 900, but does not include a turbine wheel and can include two compressor wheels on opposite sides of an electric motor.

[0045] Another embodiment takes the form of an electrically driven compressor including a housing, at least one compressor wheel, a shaft supported within the housing and interconnected with the at least one compressor wheel, an electric motor disposed within the housing and operably coupled to the shaft, and at least one compressor rolling element bearing disposed about the shaft on a compressor side of the electric motor. In such an embodiment, the compressor-side rolling element bearing includes an inner ring 110 having an outer diameter defining an inner raceway 114, an outer ring 120 having an outer diameter and an inner diameter 124, an oil jet 202 configured to provide lubrication to the inner raceway 114, where the outer ring 124 defines an outer raceway 126, a single row of rolling elements 130 between the inner raceway 114 and the outer raceway 126, a squeeze film damper 140 integrated with the outer ring 120 to form a single component, where the squeeze film damper 140 provides a squeeze film damper surface 144 between the outer ring outer diameter and the housing, and an end stop flange matable with the outer ring 120 and attached to the outer ring 120 with a snap ring. The end stop flange is rotationally restrained relative to the outer ring 120 and further engages an anti-rotation feature on the housing.

[0046] Although the foregoing detailed description has been provided in connection with certain specific embodiments, it should be understood that the scope of the present disclosure should not be limited to such embodiments, and the scope and spirit of the present disclosure is broader than the embodiments specifically disclosed and contained within the following claims.

[0047] Furthermore, although certain features are described in connection with certain embodiments, these features are not limited to use in only the described embodiment, but rather aspects of the specific embodiment can be combined with or substituted for other features disclosed in connection with alternative embodiments.

Claims

1. 1. A rolling element bearing assembly for an electrically assisted turbocharger, the bearing assembly comprising: an inner ring having an outer diameter defining an inner raceway; an outer ring having an outer diameter and an inner diameter, the outer ring inner diameter defining an outer raceway; a single row of rolling elements between the inner and outer raceways; and a squeeze film damper formed integrally with the outer race, the squeeze film damper providing a squeeze film damper surface between an outer race outer diameter and a housing; the outer ring has an end stop flange integral with the outer ring forming a single component, the end stop flange extending radially of the squeeze film damper surface and defining a boundary adjacent the squeeze film damper surface; Bearing assembly.

2. The bearing assembly of claim 1 further comprising an oil jet within said outer ring.

3. The bearing assembly of claim 1 , wherein the end stop flange is configured to engage the housing.

4. The bearing assembly of claim 3 , wherein the end stop flange includes an anti-rotation feature configured to engage the housing.

5. An electrically assisted turbocharger, housing; Turbine wheel; Compressor wheel; a shaft supported within said housing and interconnecting said turbine wheel and said compressor wheel; an electric motor disposed within the housing and operably coupled to the shaft; and at least one rolling element bearing assembly surrounding the shaft, the at least one rolling element bearing assembly comprising: Inner circle; Outer ring; A plurality of rolling elements between the inner ring and the outer ring; and a squeeze film damper integrated into the outer ring to provide a squeeze film damper surface between an outer diameter of the outer ring and the housing; the outer ring has an end stop flange integral with the outer ring forming a single component, the end stop flange extending radially of the squeeze film damper surface and defining a boundary adjacent the squeeze film damper surface; Electrically assisted turbocharger.

6. The turbocharger of claim 5 further comprising an oil jet in the outer ring.

7. The turbocharger of claim 5 , wherein the end stop flange is configured to engage the housing.

8. The turbocharger of claim 7 , wherein the end stop flange includes an anti-rotation feature configured to engage the housing.

9. 9. The turbocharger of claim 8, wherein the anti-rotation feature of the end stop flange includes a pin opening configured to engage an anti-rotation pin.

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