Effects of Ball’s Rolling, Gyroscopic, and Spin Slide in a Ball Bearing on Raceway’s Stress and Fatigue Life

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Zhuang Chen ◽  
Guanci Chen
Keyword(s):  
Fatigue Life ◽  
Friction Coefficient ◽  
Contact Mechanics ◽  
Friction Force ◽  
Ball Bearing ◽  
Equivalent Model ◽  
Element Calculation ◽  
Heavy Load ◽  
Friction Forces ◽  
Bearing Life

Abstract The motions between the ball and raceway in a ball bearing involve rolling, gyroscopic, and spin slide. These complex motions result in the serious distribution of the friction force. Based on the contact mechanics in tribology, the friction force greatly affects stress and fatigue life. Thus, it is necessary to figure out the effects of the motions and its friction force of ball–raceway contact on the fatigue life of a ball bearing. In this paper, first, the equivalent model of ball–raceway contact was studied and established for the convenience of finite element calculation. Second, the contact mechanics considering the friction force with the friction coefficient from 0 to 0.3 was computed. The influences of the motions and its friction forces of ball–raceway contact on the raceway’s stress were analyzed. Third, based on different structure fatigue life algorithms, the raceway’s fatigue life of the cases with the friction coefficient 0, 0.05, 0.1, and 0.3 were studied. The raceway’s fatigue life based on ISO 281-2007 bearing life theory is studied. Results show that the friction force on the contact surface has some influence on the stress and fatigue life to a certain extent. Especially, the ball’s spin has the greatest influence on the stress distribution and fatigue life of the raceway. Thus, for the cases of heavy load and high friction coefficient, the effect of the friction force of ball–raceway contacts cannot be neglected.

Experimental Study of a Variable Pressure Damper on Automotive Valve Motion

1996 ◽  
Author(s):  
Jin-Jang Liou ◽  
Grodrue Huang ◽  
Wensyang Hsu
Keyword(s):  
Experimental Study ◽  
Friction Coefficient ◽  
Friction Force ◽  
High Speed ◽  
Experimental Results ◽  
Variable Pressure ◽  
Friction Forces ◽  
Valve Spring ◽  
Valve Motion

Abstract A variable pressure damper (VPD) is used here to adjusted the friction force on the valve spring to investigate the relation between the friction force and the valve bouncing phenomenon. The friction force on the valve spring is found experimentally, and the corresponding friction coefficient is also determined. Dynamic valve displacements at different speeds with different friction forces are calibrated. Bouncing and floating of the valve are observed when the camshaft reaches high speed. From the measured valve displacement, the VPD is shown to have significant improvement in reducing valve bouncing distance and eliminating floating. However, experimental results indicate that the valve bouncing can not be eliminated completely when the camshaft speed is at 2985 rpm.

Analytical determination of the optimal clearance for the fatigue life of ball bearing under different load conditions

2021 ◽  
pp. 1-28
Author(s):  
Bin Fang ◽  
Jinhua Zhang
Keyword(s):  
Fatigue Life ◽  
Load Distribution ◽  
Life Prediction ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Analytical Determination ◽  
Parameters Selection ◽  
Bearing Life ◽  
Structural Design Optimization ◽  
Load Conditions

Abstract In this paper, a comprehensive analytical model for the fatigue life prediction of ball bearing in various operating conditions is presented. Not only the internal clearance variations induced by the centrifugal expansion and assembly interference, but also ball inertia forces and ball-raceway separations are fully considered in theoretical modeling to achieve accurate life prediction of ball bearing. The model has been validated by comparison with the static results in previous literature. Based on this, the results of the load distribution and fatigue life versus the internal clearance of ball bearing under various operating conditions are studied. The results show that there is always an optimal clearance to maximize bearing fatigue life for the radial load or the combined load conditions, and the size of the optimal clearance for bearing life is determined by both the load conditions and rotating speeds to ensure the uniformity of the internal load distribution of the ball bearing. Therefore, the above theoretical and conclusions can be used in structural design optimization and assembly parameters selection of ball bearing to maximize the life characteristic.

scholarly journals Analyses of contact forces and kinetic motion on heavy load ball-screw

2018 ◽  
Vol 185 ◽  
pp. 00014
Author(s):  
Chin-Chung Wei ◽  
Wen-Hsien Kao
Keyword(s):  
Contact Angle ◽  
Fatigue Life ◽  
Friction Coefficient ◽  
Phase Angle ◽  
Contact Angles ◽  
Contact Forces ◽  
Ball Screw ◽  
Transmission Performance ◽  
Heavy Load ◽  
Sinusoidal Function

Effects of contact angle and groove factor of a heavy load ball-screw are discussed with the variation of contact forces at eight ball circulations. Contact forces are varying as a sinusoidal function of each circulation owing to the variation of phase angle. With the increase of contact angles, contact forces at each ball circulation are decreased and variation in each ball circulation. The decrease of the contact forces means that the contact stresses of contact areas are reduced. Fatigue life of raceways can thus be extended. Low groove factor can reduce skidding speed and friction coefficient. By the analyzing results, optimal transmission performance can be achieved in a heavy-loaded ball-screw.

Forced Response of Shrouded Blades With Intermittent Dry Friction Force

2008 ◽  
Author(s):  
Weiwei Gu ◽  
Zili Xu ◽  
Lv Qiang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Forced Response ◽  
Gap Size ◽  
Algebraic Equations ◽  
Friction Damper ◽  
Friction Forces ◽  
Contact Points

The gap friction damper model is presented in this paper, which is employed to simulate the friction forces at the contact points of the shroud interface. Using the harmonic balance method (HBM), the friction force can be approximated by a series of harmonic functions. The governing differential equations of blade motion are transformed into a set of nonlinear algebraic equations, which can be solved iteratively to yield the steady-state response. The results show that the forced response is attenuated due to the additional damping introduced by frictional slip. The predicted results agree well with those of the Runge-Kutta method. In addition, the effect of parameters of damping structures such as the gap size, friction coefficient and normal load on the forced response of blades were studied. The results show that increasing the damper gap size causes a increase in resonant response. However, the increment isn’t obvious. In addition, an increase in friction coefficient or normal load decreases the forced response of blade.

New Hypothesis of Friction and Its Application to Design of a Railway Wheelset

1999 ◽  
Vol 121 (4) ◽  
pp. 768-773
Author(s):  
A. Fridberg ◽  
L. Vinnik
Keyword(s):  
Contact Mechanics ◽  
Friction Force ◽  
Normal Load ◽  
Friction Forces ◽  
Railway Wheel ◽  
Elastic Bodies ◽  
Tractive Effort ◽  
Wheel Rolling ◽  
New Hypothesis

A new hypothesis for friction forces between two elastic bodies is proposed. The hypothesis is based on contact mechanics problem. The study concentrates on the problem of a railway wheel rolling on rail under tractive effort and normal load. The effect of friction force in developing adhesion is considered. Based on the proposed hypothesis, new design of a railway wheelset has been developed and tested on Moscow Metro and tramcar.

Friction Forces in a Linear-Guideway Type Recirculating Ball Bearing Under Grease Lubrication

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Hiroyuki Ohta ◽  
Kazunori Oguma ◽  
Koji Takane ◽  
Soichiro Kato
Keyword(s):  
Friction Force ◽  
Ball Bearing ◽  
Internal Space ◽  
Filling Rate ◽  
Grease Lubrication ◽  
Friction Forces ◽  
Contact Voltage ◽  
Measured Time ◽  
Time Average ◽  
Differential Slip

Abstract This paper deals with friction forces in a linear-guideway type recirculating ball bearing (linear bearing) under grease lubrication. During the experiments, the friction force, temperature, and electric contact voltage of a grease lubricated linear bearing (test bearing) without seals were measured. Experimental results showed that the measured friction forces of the test bearing were fluctuated with the ball passage period. The measured time-average friction force FAVG (measured FAVG) was nearly constant when the grease filling rate x (=grease filling volume/internal space of the bearing) ≥0.13, while the measured FAVG decreased as x decreased when x < 0.13. In addition, the measured temperatures were almost constant, and the measured contact voltages indicated that the contacts of the balls and raceways were electrically insulated by the grease film. Next, the expressions of friction forces due to differential slip (FD), elastic hysteresis loss (FE), and rolling traction (FRT) were shown. The calculated FD + FE + FRT for the test bearing was almost equal to the measured FAVG around the grease filling rate of x = 0, while in cases where x > 0, the measured FAVG was greater than the calculated FD + FE + FRT. This means that when x > 0, an agitating resistance (FA) from the grease might cause the measured FAVG to be greater than the calculated FD + FE + FRT. Finally, an expression for the friction force of a linear bearing, FAVG = FD + FE + FRT + FA (which can estimate the measured ones) is proposed.

A Dynamic Friction Model for Unlubricated Rough Planar Surfaces

2003 ◽  
Vol 125 (4) ◽  
pp. 788-796 ◽  
Author(s):  
Xi Shi ◽  
Andreas A. Polycarpou
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Harmonic Excitation ◽  
Published Data ◽  
Dynamic Friction ◽  
Time Varying ◽  
Friction Forces ◽  
Dynamic Friction Coefficient ◽  
Normal Separation ◽  
The Mean

Modeling dynamic or kinetic friction for realistic engineering surfaces continues to be a challenge, partly due to the coupling between system dynamics and interfacial forces. In this paper, a dynamic friction coefficient model for realistic rough surfaces under external normal vibrations is developed. From the system dynamic model, the instantaneous time varying normal separation at the interface is obtained under normal harmonic excitation. Subsequently, the instantaneous dynamic contact and tangential (friction) forces are calculated as a function of the instantaneous normal separation. The dynamic friction coefficient defined as the ratio of the time varying friction to the interfacial normal forces that explicitly includes interfacial damping, is also calculated. The results show that a mean increase in the instantaneous normal separation may or may not lead to a decrease of the mean friction force and the mean friction coefficient, which is supported by published data. For unlubricated elastic sliding contact conditions considered in this paper, the effect of damping on the dynamic friction coefficient is found to be negligible, whereas loss of contact causes significant apparent dynamic friction force and dynamic friction coefficient reductions. Several different interpretations of the time varying dynamic friction coefficient are presented and the implications of using a simple constant value to represent the time varying dynamic friction coefficient are discussed.

scholarly journals Method for determining the coefficient of friction between fence and scraped object in equilibrium of the friction force

2018 ◽  
Vol 19 (6) ◽  
pp. 790-794
Author(s):  
Mirosław Wolski ◽  
Tomasz Piątkowski ◽  
Przemysław Osowski
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Coefficient Of Friction ◽  
Conveyor Belt ◽  
Determination Method ◽  
Friction Forces ◽  
The Coefficient Of Friction

In this paper presents friction coefficient determination method between scraped object's material and fence material, determined directly on the conveyor belt, which then is introduced in the FEM program (LSDyna) for simulation of the scraping process in the automated sorting plant. In this case, the necessity of using an additional laboratory stand to determine the coefficient of friction is omitted. Due to the existing balance of friction forces, the model of the phenomenon can be treated as static, therefore the measurement is very simple and does not depend on time.

IMPACT OF ADHESION AND VISCOSITY FORCES ON FRICTION VARIATIONS IN BIO-TRIBOLOGICAL SYSTEMS

Tribologia ◽  
2018 ◽  
Vol 278 (2) ◽  
pp. 139-151
Author(s):  
Krzysztof WIERZCHOLSKI ◽  
Andrzej MISZCZAK
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Hydrodynamic Pressure ◽  
Hydrogen Ion ◽  
Phospholipid Bilayer ◽  
Ion Concentration ◽  
Experimental Investigations ◽  
Hydrogen Ion Concentration ◽  
Friction Forces ◽  
Lubricant Viscosity

The classical theory of lubrication holds that the lubricant dynamic viscosity increments cause the increments of hydrodynamic pressure, as well as friction forces and wear. In the case of high values of hydrodynamic pressure, it very often has a significant impact on the friction coefficient. New achievements in the field of micro-and nano-tribology provide for new hypotheses on the decrements and increments of the friction coefficient in the case of the lubricant viscosity increments. Experimental investigations have shown that, even in the case of decrements of the friction coefficient with the lubricant viscosity increments, such decrements are very often lower than simultaneous hydrodynamic pressure increments which results in the friction force increments with the lubricant viscosity increments. In biological friction nods, we can observe a varied impact of the biological lubricant viscosity on the friction force and friction coefficient values. The abovementioned impact is caused by the adhesion and cohesion forces occurring between the biological fluid particles flowing around the phospholipid bilayer on the superficial layer of the cartilage with varied wettability and hydrogen ion concentration. The wettability (We) and power hydrogen ion concentration (pH) have a significant impact on the physiological fluid or biological lubricant viscosity variations and, as a result, on the friction forces and friction coefficient. This paper describes the abovementioned impact and the process of friction forces and friction coefficients variations in biological friction nods.

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