A bearing assembly (1) for preload measurement, having at least one rotary element (2, 3), wherein the at least one rotary element (2, 3) includes a radial (4) and/or axial receptacle (5) for a rolling bearing (6), wherein the at least one rotary element (2, 3) includes at least one measurement device (7, 8) in the region of the receptacle (4, 5) for measuring the rolling bearing preload, and wherein the at least one measurement device (7, 8) is located inside the at least one rotary element (2, 3).

A rolling bearing includes a first ring, a second ring, at least one row of axial rolling elements arranged between the first ring and the second ring, and at least one thrust ring axially interposed between the axial rolling elements and the first ring and delimiting a raceway for the axial rolling elements. At least one spring system axially biases the thrust ring against the axial rolling elements and includes a piston housed in a through-hole of the first ring and a spring element pressing the piston against the thrust ring. The piston includes a threaded hole accessible from outside the first ring.

A rolling bearing includes a first ring, a second ring, at least one row of axial rolling elements arranged between the first ring and the second ring, and at least one thrust ring axially interposed between the axial rolling elements and the first ring and delimiting a raceway for the axial rolling elements. At least one spring system axially biases the thrust ring against the axial rolling elements and includes a piston housed in a through-hole of the first ring and a spring element pressing the piston against the thrust ring. The piston includes a threaded hole accessible from outside the first ring.

A load-variable rolling bearing includes: an outer ring having an outer ring raceway surface with spherical surface contact portions having concave arch sections and a variable contact portion having a shape of a cylinder in such a manner as to be adjacent to the spherical surface contact portions in an axial direction of the spherical surface contact portions; an inner ring having an inner ring raceway surface with spherical surface contact portions having concave arch sections and a variable contact portion having a shape of a cylinder in such a manner as to be adjacent to the spherical surface contact portions in an axial direction of the spherical surface contact portions; and a plurality of rolling elements each having a cylindrical variable contact portion and spherical surface portions formed with convex spherical surfaces on both sides of the variable contact portion.

Systems and methods for cooling power transmission systems are include providing oil through an aperture defined in a housing to a stator cooling ring, through the stator cooling ring and into stator cooling channels, through the stator cooling channels and into spaces defined between the housing and jet rings, and through holes in the jet rings and onto the end-windings. The stator cooling ring, stator cooling channels and jet rings can encircle the stator and end-windings and, via the holes in the jet rings, spray pressurized jets of oil from various angles onto the end-windings, and in particular middle regions thereof. Seals may be used between the jet rings and housing, and between the jet rings and stator ends. The seals may be compressed so as to form an interference fit between the jet rings and housing or stator ends as the case may be.

In the present invention, in a housing that supports a rotating shaft via a rolling bearing which is subjected to predetermined position precompression, a wedge member, the radial thickness of which increases from the leading end towards the base end thereof, is inserted between the housing and the outer circumferential surface of the outer race of the rolling bearing and between the rotating shaft and the inner circumferential surface of an inner race of the rolling bearing, the wedge member being inserted from the leading end thereof along the radial direction of the rotating shaft. The wedge member is fixed by being fastened, ahead in the insertion direction, by bolts and nuts, so that precompression force along with predetermined position precompression is imparted to the rolling bearing.

In the present invention, in a housing that supports a rotating shaft via a rolling bearing which is subjected to predetermined position precompression, a wedge member, the radial thickness of which increases from the leading end towards the base end thereof, is inserted between the housing and the outer circumferential surface of the outer race of the rolling bearing and between the rotating shaft and the inner circumferential surface of an inner race of the rolling bearing, the wedge member being inserted from the leading end thereof along the radial direction of the rotating shaft. The wedge member is fixed by being fastened, ahead in the insertion direction, by bolts and nuts, so that precompression force along with predetermined position precompression is imparted to the rolling bearing.

A method of determining bearing preload by vibration measurement including mounting the bearing on a vibration tester, the outer ring clamped preventing rotation, mounting a sensor proximate the outer ring to measure vibration, the bearing inner ring rotated to excavate eigen-frequencies, the measured vibration data transmitted from the sensor to a computer workstation, the computer workstation performs a numerical FFT transforming data to Frequency Domain, spectral data from the FFT analyzed with the computer workstation, a peak detection algorithm determines the peaks that are the various modes of the outer ring, the modes are sorted and main modes identified, numerical relationship is obtained for each mode between the resonance and preload, the mode relationships are compared to one or more references, a match between the numerical relationships for each mode and the ideally referenced graph modes indicates a correct preload is determined. Also, a system for carrying out the method.

A method of determining bearing preload by vibration measurement including mounting the bearing on a vibration tester, the outer ring clamped preventing rotation, mounting a sensor proximate the outer ring to measure vibration, the bearing inner ring rotated to excavate eigen-frequencies, the measured vibration data transmitted from the sensor to a computer workstation, the computer workstation performs a numerical FFT transforming data to Frequency Domain, spectral data from the FFT analyzed with the computer workstation, a peak detection algorithm determines the peaks that are the various modes of the outer ring, the modes are sorted and main modes identified, numerical relationship is obtained for each mode between the resonance and preload, the mode relationships are compared to one or more references, a match between the numerical relationships for each mode and the ideally referenced graph modes indicates a correct preload is determined. Also, a system for carrying out the method.

In accordance with one aspect of the present disclosure, a turbocharger having a rolling element bearing (REB) assembly contained within a bearing housing includes an axial damper configured to dampen and limit axial displacement of the REB assembly. The axial damper can include different embodiments, including an elastomeric axial damper, wire mesh, or oil film, for interrupting contact between the bearing assembly and a displacement limit when an axial displacement force exceeds a preload force. Further, the axial damper can include an apparatus having at least two axially compressible rings, where one of the axially compressible rings includes a displacement limit feature.