Analysis Of Ball Bearings Research Articles

Effect of elastohydrodynamic lubrication on the dynamic analysis of ball bearing

A numerical dynamic analysis of ball bearing is presented. The normal contact forces between balls and races are calculated, respectively, based on Hertz contact theory and elastohydrodynamic lubrication theory, and the results are compared to study the effect of elastohydrodynamic lubrication on the simulation. The dynamic model of ball bearing is developed with the assumptions that outer race is fixed in space and other elements have six degrees of freedoms. The lubricant film between balls and races is equivalent as the spring–damper system when elastohydrodynamic lubrication effect is considered. The equations of motion are solved by the fourth-order Runge-Kutta integration method with variable steps. The results indicate that the effect of elastohydrodynamic lubrication has great influence on the dynamic analysis result when the load is slight. As the load increases, the effect of elastohydrodynamic lubrication becomes small.

Analysis of Ball Bearings under Dynamic Loading Using Non- Destructive Technique of Thermography

Roller bearing defect is a major factor of failure in rotating machinery that affects proper functioning of system which results in substantial time and economic losses. Therefore, condition monitoring of roller bearing is important and the study of severity of defects are necessarily required in order to avoid catastrophic consequences. Defects monitoring during dynamic loading conditions of rotational machineries with the use of contactless, non-destructive infrared thermographic method is proposed. By using a rotating ball bearing, passive thermographic experiment was performed as an alternative technique to proceed the condition monitoring. Based on the results, the temperature characteristics of the ball bearing under dynamic loading conditions were analyzed thoroughly. Also, a comparison of these results was done for different bearings with characteristic defects. As a result, it was confirmed that infrared thermography method could be adopted to monitor and diagnose the faults by evaluating quantitatively and qualitatively the temperature characteristics according to the condition of the ball bearing.

Finite Element Analysis for Thermal Characteristics of High Speed Angular Contact Ball Bearing

According to the high speed bearing failure problem caused by the high temperature, finite element model of high-speed hybrid ceramic angular contact ball bearing is established in this paper. Quantity of heat and heat transfer coefficient are calculated by using the heat transfer and thermodynamics theory, which are boundary condition for the temperature field simulation analysis of ball bearing. The temperature distribution of bearing is obtained when bearing speed is 12000rad/min. The results can provide a theoretical foundation for lubrication cooling system controlling temperature.

J101013 液体水素からの力とモーメントを考慮したターボポンプ用玉軸受の動力学解析(〔J101-01〕回転機械のダイナミック設計(1))

J101013 液体水素からの力とモーメントを考慮したターボポンプ用玉軸受の動力学解析(〔J101-01〕回転機械のダイナミック設計(1))

Experimental testing and thermal analysis of ball bearings

The evolution of temperature with time in a deep-groove ball bearing in an oil-bath lubrication system is studied both experimentally and analytically. The test apparatus is a radially-loaded ball bearing instrumented to measure the frictional torque as well as the transient temperature of the outer race, oil and housing. The mathematical model developed provides a comprehensive thermal analysis of the ball bearing with provision for frictional heat generation, heat transfer processes and thermal expansion of bearing components. Experiments are performed for different speeds and loads to validate the model. The predicted temperatures under different loads and speeds are found to be in close agreement with those measured experimentally. Simulations results indicate that higher rotational speed, oil viscosity and housing cooling rate lead to the larger temperature gradient and thermally-induced preload in ball bearings.

Vibration analysis of ball bearings with a localized defect applying piecewise response function

The amplitude and time duration of the impulse generated by a ball bearing passing over a local defect on the race are determined by the shape and size of the local defect. To identify the operation status of the bearing an accurate relationship between the impulse response and the size and shape of the local defect is necessary. In this paper, a dynamic simulation method is proposed to study ball bearing with local defect based on the coupling of the piecewise function and the Hertzian contact mechanism at the edge of the local defect. The ball bearing is modeled as a two-degree of freedom system. The impulse force is determined by the ratio of the ball size to the defect size and the contact deformation at the edge of the local defect is included. The contact mechanical characteristics between the ball and the race with different defect sizes are studied and compared with available results in the literature. It is shown that the proposed method can provide a more close to real impulse for the contact between the ball and the race with different defect sizes compared to the assumed rectangular or half-sine impulse function. It is also shown that the proposed method provides a new method for dynamic simulation of ball with a localized defect.

Quasi-static analysis of thrust-loaded angular contact ball bearings part I: theoretical formulation

Ball bearings play an important role in various rotating machineries, but the complicated kinematic and tribological features of ball bearings make many aspects of their operating behaviors still inconclusive. Most theoretical analyses of ball bearings up to date are based on either the hypothesis of race control or other empirical models to determine the ball motion of ball bearings, but none of these strategies can reveal and consequently employ the intrinsic coupling mechanism between the spin and the tangential traction of contacting bodies rolling upon one another. To remedy the deficiency of current analytical models for ball bearing analysis, the rolling contact theory is employed to establish an explicit link between motions and interactions within ball bearings. A differential slip model is established to precisely define the slip component due to the significant curvature of the common contact patches between the ball and inner/outer raceways. The creepage and the spin ratio are formulated to accurately define the relative rigid motion between the ball and the inner/outer raceway. Then a quasi-static analytical model is established that can accurately determine the motions of the balls and races of the ball bearing. It can also give a vivid description of the slip and traction distributions within the contact area. The analytical model can be effectively used to analyze the operational conditions and tribological features of solid-lubricated ball bearings. It can also be used optimize the construction of ball bearings for specific applications.

Application of Genetic Algorithm in Numerical Solution of Analysis Model for Angular-Contact Ball Bearings

In this paper, an angular contact ball bearing analysis model has been established based on Hertz contact theory. Solving nonlinear equations by improved genetic algorithm (IGA) and verified the effectiveness of the method through numerical experiment. The results proved that the adoption of IGA to solve the analysis model of angular contact ball bearing, can effectively resolve the problem of the Newton-Raphson method such as no convergence and need initial value, the calculation results is satisfied.

Metallurgical Analysis of Ball Bearing Seized During Operation

440C stainless steel of martensitic grade is being extensively used for bearing application because of its high wear and corrosion resistance. This alloy steel with 1 wt.% C along with 17 wt.% Cr, 1 wt.% Mn and up to 0.75 wt.% Mo has a number of primary carbides, which provide high hardness and good wear resistance. Owing to its unique performance characteristic, this steel finds a number of applications in space program. One such application is bearing used in booster pump assembly of propulsion system. During one of the ground tests of propulsion system, booster pump bearing seized operation after performing its partial intended function. The bearing was removed from the assembly and cut open. The ball and outer caging were analyzed using metallographic techniques and compared with another bearing taken from the fresh stock. Study indicated that ball as well as outer caging experienced exposure to high temperature and resulted in phase transformation. This article highlights the details of investigations carried out.

Scalable total BETI based solver for 3D multibody frictionless contact problems in mechanical engineering

A total BETI (TBETI) based domain decomposition algorithm with the preconditioning by a natural coarse grid of the rigid body motions is adapted for the solution of multibody frictionless contact problems of linear elastostatics and proved to be scalable, i.e., the cost of the solution is asymptotically proportional to the number of variables. The analysis admits floating bodies. The proofs combine the original results by Langer and Steinbach on the scalability of BETI for linear problems and our development of optimal quadratic programming algorithms for bound and equality constrained problems. The theoretical results are verified by numerical experiments. The power of the method is demonstrated on the analysis of ball bearings.

Analysis of Ball Bearings with 2, 3 or 4 Contact Points

An analysis of an arched ball bearing that considers centrifugal forces and gyroscopic effects is performed. Based on operating conditions of a 5 DOF inner ring and Coulomb friction model, the conventional bearing theory is extended from 2 to 3 and 4 contacts. The commonly used control criterion of a ball bearing by the inner or outer raceway is debatable and is known to fit experimental data with difficulty, and when more than two contact points are involved it becomes obsolete. The paper presents a mathematical model to describe the ball internal kinematics under the effect of the operating conditions. This analysis makes it clear that the total power loss varies strongly with the one or two added sources of friction. The maximum PV factor is also affected by the full sliding of the lightly loaded contacts induced by the arched design.

English

Squirrel cage ball bearings are used in recent aero engines to overcome the vibration andstability problems associated with rotor systems supported by conventional bearings. The criticaldesign feature of squirrel cage bearing is to provide flexible support to rotor system. The outerring of the bearing is configured such that it acts as a flexible bearing support, and hence, weightis minimised. The bearing is mounted directly on a rigid intermediate casing of a gas turbineengine. Finite element analysis helps to obtain a suitable geometry at the design stage. A 3-Dmodel of the bearing is created using IDEAS software. Finite element analysis using contactelement has been carried out for finding the deformation and stresses in the webs at variouslocations using ANSYS software. The deformations are compared with those of experimentalvalues for an axial load. The deformation in the webs is used to check the pressure balance inthe compressor and the load acting on the bearing. Finally, a procedure for doing the finiteelement analysis of ball bearings for combined axial and radial load is laid down.

Application of the EMD method in the vibration analysis of ball bearings

In this paper, the empirical mode decomposition (EMD) method is introduced and the calculation of the local mean with the envelope method of the extrema is substituted by an improved method, in which the local mean is computed by using the average method of the successive extrema. Based on the improved EMD method, the vibration signals of ball bearings are analyzed in detail. The results show that the proposed method is superior to the discrete wavelet decomposition for the vibration analysis of ball bearings.

High-speed ball bearing analysis

The most frequently used ball bearing analysis and design computer programs are based on a quasi-static analysis of the ball dynamics which is fast and convenient, but involves assumptions that can be poor. The alternatives use a time-marching dynamic analysis that provides a better representation of the physics, but is too slow for use as a routine design tool. This article uses ideas that came from the experimental work to overcome a major assumption in the quasi-static analysis while allowing analysis of combined load bearings in real time on a standard PC.

Analysis Of Ball Bearings Using Optimization Techniques

In detailed analysis of ball bearings, there are multiple non-linear equations that need to be solved. Newton-Raphson iteration technique is usually used for solving the resulting system of non-linear equations. To solve for the perturbations during the iterative process matrix inversion is frequently needed. Finding the inverse of a matrix is costly and increases sharply with matrix size. In this paper, optimization techniques are used to efficiently solve the multiple systems of non-linear equations. The BFGS optimization method is used to reduce the computational cost and time. The proposed approach with the necessary modifications such as scaling, are presented in the paper along with some test cases.

Vibration Analysis of Ball Bearing Caused By Passing Rolling Elements Considering Misalignment on Outer Ring.

Vibration Analysis of Ball Bearing Caused By Passing Rolling Elements Considering Misalignment on Outer Ring.

Reduction of NRRO in a Ball Bearing for HDD Spindle Motors. (2nd Report. Experimental Analysis of Ball Bearing with 12 balls).

In this paper, we experimentally analyzed the non-repeatable run-out (NRRO) of a ball bearing to confirm the theoretical analysis proposed in the previous paper and the advantage of a ball bearing with 12 balls for NRRO. The results are summarized as follows: (1) Since NRRO calculated by actual geometrical errors of ball bearing parts was nearly equal to the measured NRRO, it was clarified that the theoretical analysis in the previous paper was valid. (2) NRRO of a ball bearing with 12 balls was very small even if geometrical errors of ball bearing parts was large. It was confirmed that 12 was suitable ball number for ball bearings used in HDD spindle motors.

Location of an acoustic emission source in a radially loaded deep groove ball-bearing

This paper describes a deep groove ball-bearing analysis which has been developed to simulate acoustic emission occurring during ball-bearing operation. The computer simulation is useful to clarify experimental research on rolling contact fatigue initiation using the acoustic emission technique. Results show the ability of the method to detect and to locate a subsurface defect, due to rolling contact fatigue, before the rolling bearing failure occurs. The subsurface defect can be accurately located within the inner ring of a deep groove ball-bearing operating under radial load.

Vibration Analysis of Ball Bearing caused by Outer Ring Waviness.

Vibration Analysis of Ball Bearing caused by Outer Ring Waviness.