scholarly journals Studies on the Vibrations of Ball Bearing under Radial Load. 2nd Report. Rigid-Body Natural Vibration of Outer Ring.

1993 ◽  
Vol 59 (562) ◽  
pp. 1857-1861 ◽  
Author(s):  
Hiroyuki Ohta ◽  
Masanori Yuri
Keyword(s):  
Rigid Body ◽  
Natural Vibration ◽  
Ball Bearing ◽  
Outer Ring ◽  
Radial Load

Vibrations of the All-Ceramic Ball Bearing

2002 ◽  
Vol 124 (3) ◽  
pp. 448-460 ◽  
Author(s):  
Hiroyuki Ohta ◽  
Shinya Satake
Keyword(s):  
Natural Vibration ◽  
Ball Bearing ◽  
Axial Direction ◽  
Outer Ring ◽  
Ball Bearings ◽  
Ceramic Ball ◽  
Vibration Spectra ◽  
All Ceramic ◽  
Hybrid Ceramic ◽  
Mass Type

All-ceramic ball bearings with silicone nitride balls and silicone nitride rings were tested and the vibration characteristics were compared with those of hybrid ceramic ball bearings and conventional steel ball bearings. The vibration measurement results showed that the overall vibratory velocity levels of the all-ceramic ball bearings are influenced by rotational velocities, and do not change with axial loads. Under a given axial load and rotational velocity, the overall vibratory velocity level of the all-ceramic ball bearing is the lowest, and the hybrid ball bearing the highest. The frequencies of main peaks in the measured vibration spectra of the all-ceramic ball bearing are higher than the frequencies of the corresponding main peaks for the hybrid ceramic ball bearing and the steel ball bearing. To explain the main peaks, modal analysis was done and the relationship between peak and natural vibration was analyzed. The results of the analyses showed that the main peaks are caused by: (1) the mass-type natural vibration of the outer ring in the vertical direction, (2) the bending natural vibration of the outer ring in the radial direction, (3) the moment of inertia-type natural vibration of the outer ring in the angular direction, (4) the mass-type natural vibration of the outer ring in the axial direction, and (5) the bending natural vibration of the outer ring in the axial direction. We also discuss the generating mechanism of the vibration and present the calculation method of the vibration spectra. As a result, it is clear that the vibration spectra of the all-ceramic ball bearing are determined by the amplitude of the waviness of the raceways and ball surface, the mobility, and the non-linear spring constant associated with the contact between the raceways and balls.

Direct Outer Ring Cooling of a High Speed Jet Engine Mainshaft Ball Bearing: Experimental Investigation Results

2010 ◽  
Author(s):  
Peter Gloeckner ◽  
Klaus Dullenkopf ◽  
Michael Flouros
Keyword(s):  
Power Dissipation ◽  
High Speed ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Outer Ring ◽  
Outer Diameter ◽  
Propulsion Systems ◽  
Jet Engine ◽  
Power Loss Reduction ◽  
The Impact

Operating conditions in high speed mainshaft ball bearings applied in new aircraft propulsion systems require enhanced bearing designs and materials. Rotational speeds, loads, demands on higher thrust capability, and reliability have increased continuously over the last years. A consequence of these increasing operating conditions are increased bearing temperatures. A state of the art jet engine high speed ball bearing has been modified with an oil channel in the outer diameter of the bearing. This oil channel provides direct cooling of the outer ring. Rig testing under typical flight conditions has been performed to investigate the cooling efficiency of the outer ring oil channel. In this paper the experimental results including bearing temperature distribution, power dissipation, bearing oil pumping and the impact on oil mass and parasitic power loss reduction are presented.

Motions of an Unstable Retainer in an Instrument Ball Bearing

1994 ◽  
Vol 116 (2) ◽  
pp. 202-208 ◽  
Author(s):  
E. Kingsbury ◽  
R. Walker
Keyword(s):  
Experimental Investigation ◽  
Rigid Body ◽  
Rotation Rate ◽  
High Frequency ◽  
Ball Bearing ◽  
Stable Operation ◽  
Frequency Content ◽  
Outer Race ◽  
Group Rotation ◽  
Inner Race

We made an experimental investigation of the motions of the retainer in an instrument ball bearing during stable operation and during squeal. Radial motions of the retainer were measured with two fiber-light probes mounted 90 physical degrees apart. A signal analyzer was used to determine the phasing and frequency content of the probe signals. During squeal, a high-frequency retainer motion was found to be superimposed on the normal retainer ball group rotation rate. This high-frequency motion, which we call whirl, is a rigid-body translation in a circle. Whirl direction is opposite to the race for outer-race rotation, but in the same direction for inner-race rotation. Whirl frequency is approximately proportional to ball spin rate. The observations agree with predictions made from a squeal model based on retainer-to-ball frictional coupling that was originally presented in 1965.

Ball Bearing Vibration Analysis Including Localized and Distributed Defects

2003 ◽  
Author(s):  
Jussi T. Sopanen ◽  
Aki M. Mikkola
Keyword(s):  
Degrees Of Freedom ◽  
Ball Bearing ◽  
Natural Frequencies ◽  
Computer Code ◽  
Hertzian Contact ◽  
Outer Ring ◽  
Proposed Model ◽  
Deep Groove ◽  
Localized Defects ◽  
Bearing Rings

This study proposes the dynamic model of a deep groove ball bearing with six degrees of freedom. The model includes descriptions of non-linear Hertzian contact deformation and elastohydrodynamic fluid film. The geometry, material properties and diametral clearance of the bearing are given as the input to the proposed model. The bearing force and torque components are calculated from the relative displacements and velocities between bearing rings. Distributed defects such as the waviness of the inner and outer ring, and localized defects, such as inner and outer ring defects, are taken into consideration in the proposed model. The effect of the diametral clearance of the bearing on the natural frequencies and vibration response of the rotor bearing system is studied. The diametral clearance is found to have a significant effect on the level of vibration as well as on the natural frequencies. Low-order waviness, also known as out-of-roundness, is found to generate vibration at frequencies of the waviness order multiplied by the rotation speed. Localized defects in the inner and outer ring are found to generate vibrations at bearing defect frequencies. The simulation results are in line with the analytical and experimental results available in literature. The proposed ball bearing model could be used in the general multibody or rotor dynamics computer code as an interference element between the rotor and the housing.

scholarly journals Experimental and Numerical Investigation of the Outer Ring Cooling Concept in a Hybrid and in an All-Steel Ball Bearing Used in Aero-Engines by the Introduction of a Helical Duct

Aerospace ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 23 ◽  
Author(s):  
Michael Flouros ◽  
Peter Gloeckner ◽  
Markus Hirschmann ◽  
Matthias Martin ◽  
Francois Cottier ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Ball Bearing ◽  
Steel Ball ◽  
Outer Ring ◽  
Aero Engines
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