US-12627199-B2 - Rotor balance ring and oil flinger

US12627199B2US 12627199 B2US12627199 B2US 12627199B2US-12627199-B2

Abstract

A turbocharger includes a rotor rotatably mounted within the turbocharger about a rotor axis, a balance ring provided at an axial end of the rotor, and a cutout provided in the balance ring, the cutout having an open end extending radially outward from the rotor axis.

Inventors

Kurtis Erron Henderson
Michael Sean Ward

Assignees

BORGWARNER INC.

Dates

Publication Date: 20260512
Application Date: 20191125

Claims (16)

1 . A turbocharger comprising: a magnetic rotor rotatably mounted within the turbocharger about a rotor axis, the magnetic rotor having a magnetic core disposed within a shell; a balance ring disposed in and provided at an axial end of the magnetic rotor and having a base and a flange extending axially from the base away from the axial end of the magnetic rotor, the base being contained within the shell; a cylindrical shaped cutout provided in the flange of the balance ring, the cutout having an open end extending radially outward from the rotor axis and a cutout axis aligned to an axis of the magnetic rotor; a stator positioned radially outward from the magnetic rotor and axially aligned with the magnetic rotor; an airgap between an inner surface of the stator and an outer surface of the magnetic rotor; and a shaft rotatable about the rotor axis; wherein the balance ring is configured to be an oil flinger to eject oil from the cutout as the balance ring rotates, and the cutout is configured to have a diameter based on a measured imbalance of the magnetic rotor.
2 . The turbocharger of claim 1 , wherein the cutout is disposed on an outer circumferential surface of the balance ring and includes a cutout wall, the entire cutout wall being exposed to the open end.
3 . The turbocharger of claim 1 , wherein the cutout has a cutout axis that is transverse to the rotor axis and extends radially outward from the rotor axis.
4 . The turbocharger of claim 3 , wherein a height measurement between the cutout axis and an axial plane of a top surface of the flange is based on a measure of imbalance of the magnetic rotor combined with the balance ring.
5 . The turbocharger of claim 1 , wherein the cutout has a cutout axis that is parallel to the rotor axis.
6 . The turbocharger of claim 5 , wherein a radial measurement between the cutout axis and the rotor axis is based on a measure of imbalance of the magnetic rotor combined with the balance ring.
7 . The turbocharger of claim 1 , wherein the cutout is a concave cutout.
8 . A turbocharger comprising: a magnetic rotor rotatably mounted within the turbocharger about a rotor axis, the magnetic rotor having a magnetic core disposed within a shell, the magnetic rotor having a first axial end and a second axial end opposite the first axial end; a first balance ring of the magnetic rotor forming the first axial end and having a first base and a first flange extending axially from the first base past the first axial end of the rotor, the first base being located within the shell, the first flange of the first balance ring extending away from the shell and including a first cylindrical shaped cutout having a first open end extending radially outward from the rotor axis and a first cutout axis aligned to an axis of the magnetic rotor; a second balance ring of the magnetic rotor forming the second axial end and having a second base and a second flange extending axially from the second base past the second axial end of the rotor, the second base being located within the shell, the second flange of the second balance ring extending away from the shell and including a second cylindrical shaped cutout having a second open end extending radially outward from the rotor axis and a second cutout axis aligned to axis of the magnetic rotor; a stator; an airgap between the stator and the rotor; and a shaft rotatable about the rotor axis; wherein the first balance ring and the second balance ring are configured to be an oil flinger to eject oil from the first cutout and the second cutout as the first balance ring and the second balance ring rotate, and the first cutout and the second cutout are configured to have a diameter based on a measured imbalance of the magnetic rotor.
9 . The turbocharger of claim 8 , wherein: the first cutout is disposed on an outer circumferential surface of the first balance ring and includes a first cutout wall, the entire first cutout wall being exposed to the first open end; and the second cutout is disposed on an outer circumferential surface of the second balance ring and includes a second cutout wall, the entire second cutout wall being exposed to the second open end.
10 . The turbocharger of claim 8 , wherein the first cutout is a first cylindrical cutout having a first cutout axis that is transverse to the rotor axis and extends radially outward from the rotor axis, and the second cutout is a second cylindrical cutout having a second cutout axis that is transverse to the rotor axis and extends radially outward from the rotor axis.
11 . The turbocharger of claim 8 , wherein the first cutout is a first cutout having a first cutout axis that is parallel to the rotor axis and the second cutout is a second cutout having a second cutout axis that is parallel to the rotor axis.
12 . The turbocharger of claim 8 , wherein a first cutout axis of the first cutout coincides with a second cutout axis of the second cutout.
13 . The turbocharger of claim 8 , wherein either one or both of the first cutout and the second cutout is a concave cutout.
14 . A rotor for a turbocharger comprising: a magnetic core mounted on a shaft of the turbocharger, the magnetic core having a shell; a balance ring disposed on a first axial end of the magnetic core and having a base and a flange extending axially from the base away from the first axial end of the magnetic core and extending radially away from the shaft of the turbocharger, the base being contained within the shell; and a cylindrical shaped cutout provided on an outer circumferential surface of the flange of the balance ring, the cutout having an open end extending radially outward from a rotor axis and a cutout axis aligned to an axis of the magnetic core, wherein the balance ring is configured to be an oil flinger to eject oil from the cutout as the balance ring rotates, and the cutout is configured to have a diameter based on a measured imbalance of the magnetic rotor.
15 . The rotor of claim 14 , wherein a size of the cutout is based on a measure of imbalance of the magnetic core combined with the balance ring.
16 . The rotor of claim 14 , wherein the flange of the balance ring extends axially past a first end of the shell.

Description

TECHNICAL FIELD The present disclosure relates to balancing of turbocharger rotors. BACKGROUND Current methods of component balancing of magnetic rotors are accomplished by drilling or milling into an endcap of the rotor. Such drilling results in cavities that are prone to collect debris, ferrous or otherwise. The buildup of debris in the cavities may unbalance the rotating assembly above design limits and lead to a shortened lifespan of the rotor assembly or require more frequent preventative maintenance to remove the built up debris. Further, magnetic rotors are mounted on shafts lubricated by oil. There is a potential for oil to seep along the shaft into an airgap between a rotor and a stator. Oil seeping into the airgap may increase windage losses of the turbocharger and result in degraded performance. U.S. Pat. No. 8,294,319 by Shibui, et. al., discloses a rotor constituted by a motor shaft, a permanent magnet surrounding the motor shaft around the axis, a pair of end rings surrounding the motor shaft around the axis and pinching the permanent magnet, and a hollow cylindrical outer sleeve surrounding the permanent magnet and the pair of end rings in a fastening state around the axis. One end portion or both end portions of the outer sleeve protrudes in the axial direction than an end surface of the end ring. A rotating balance correction is executed by pruning away a part of the protruding portion. However, such a rotor disclosed by the '319 patent may still be improved. Thus, a rotor balance ring with an oil flinger is desired. SUMMARY In one described embodiment of the disclosure, turbocharger includes a rotor rotatably mounted within the turbocharger about a rotor axis, a balance ring provided at an axial end of the rotor, and a cutout provided in the balance ring, the cutout having an open end extending radially outward from the rotor axis. In another described embodiment of the disclosure, turbocharger includes a rotor rotatably mounted with the turbocharger about a rotor axis, the rotor having a first axial end and a second axial end opposite the first axial end, a first balance ring provided at the first axial end, the first balance ring including a first cutout having a first open end extending radially outward from the rotor axis, a second balance ring provided at the second axial end, the second balance ring including a second cutout having a second open end extending radially outward from the rotor axis, a stator, an airgap between the stator and the rotor; a shaft rotatable about the rotor axis, and an oil system to lubricate the shaft. The first and second balance rings are configured to be an oil flinger to direct oil from along the shaft towards the rotor and away from the air gap. In yet another described embodiment of the disclosure, a rotor or a turbocharger includes a balance ring disposed on a first axial end of the rotor and a cutout provided on an outer circumferential surface of the balance ring. The cutout includes an open end extending radially outward from a rotor axis. These and other aspects are disclosed in more detail in the detailed description and the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the disclosure will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements, and wherein: FIG. 1 depicts a cross-sectional view of a turbocharger, in accordance with an embodiment of the present disclosure; FIG. 2 depicts a perspective view of a first balance ring having a first cutout, in accordance with an embodiment of the present disclosure; FIG. 3 depicts a top view of the first balance ring having a first cylindrical cutout, in accordance with an embodiment of the present disclosure; FIG. 4 depicts a perspective view of a second balance ring and a rotor, in accordance with an embodiment of the present disclosure; FIG. 5 depicts a top view of the second balance ring having a second cylindrical cutout, in accordance with an embodiment of the present disclosure; and FIG. 6 depicts a cross-sectional view of a rotor and balance ring, in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS Referring initially to FIG. 1, FIG. 1 depicts a cross-sectional view of a turbocharger, in accordance with an embodiment of the present disclosure. In particular, FIG. 1 depicts the cross-sectional view 100 that includes aspects of the turbocharger 102. The turbocharger 102 includes a rotor 104, that may be realized as a magnetic rotor with a magnetic core 132 disposed between a shell 122. The rotor 104 is rotatably mounted within the turbocharger 102 to rotate about a rotor axis 106. The rotor 104 includes balance rings 108-1 and 108-2 disposed at the axial ends 110, 112 of the rotor. The balance rings 180-1 and 108-2 include bases 126-1 and 126-2, respectively, that are contained within the shell 122. The balance ring 108-1 includes a first flang