Deformation Of Bush Research Articles

A Fluid-Structure Interaction Method for the Elastohydrodynamic Lubrication Characteristics of Rubber-Plastic Double-Layer Water-Lubricated Journal Bearings

This paper proposes a fluid-structure interaction (FSI) numerical calculation method for investigation of the elastohydrodynamic lubrication performance of the rubber-plastic double-layer water-lubricated journal bearings. The accuracy and rapidity of the FSI method are improved by studying the effect of mesh density and by comparing the calculation results with those in the literature. Based on the proposed method, a series of numerical simulations are carried out to reveal the influence of operating conditions and structural parameters on the lubrication performance of the rubber-plastic bearings. Numerical results show that the bush deformation of the rubber-plastic bearing is between that of the rubber bearing and the plastic bearing, and the deformation area is close to that of the rubber bearing. The bearing load carrying capacity increases significantly with the rotational speed, eccentricity ratio, bearing length, and decrease with the clearance. But the influences of the plastic layer elastic modulus and thickness on bearing load are unremarkable. The effect of bush deformation on bearing load is noticeable when the eccentricity ratio is more than 0.8. The results are expected to provide design references for the bearings.

Study on elastohydrodynamic lubrication performance of double-layer composite water-lubricated bearings

Double-layer composite water-lubricated bearing is a new type of water-lubricated bearing which can integrate the good damping performance of low elastic under-layer bush and good tribological performance of plastic layer bush. This paper analyzes its elastohydrodynamic lubrication performance by fluid–structure interaction (FSI) method, and studies the effects of eccentricity ratio, rotational speed, elastic modulus distribution and thickness distribution of bearing bush on its lubrication performance. Results show that the lubrication performance of double-layer bearing is more like that of plastic bearing. As rotational speed and eccentricity ratio increase, the maximum water film pressure, the load carrying capacity and the maximum bush deformation increase significantly. As the elastic modulus of the low elastic under-layer bush decreases, the total bush deformation increases significantly, but the load carrying capacity decreases slightly. The bush thickness distribution influences the deformation distribution of both low elastic under-layer bush and plastic layer bush, but have little impact on the total bush deformation and bearing lubrication performance.

Study of dynamic coefficients of water film in marine stern tube bearing considering roughness and deformation

Dynamic analysis of water-lubricated marine stern tube bearing is incompatible with that of ordinary oil-lubricated bearing due to the deformation of compliant bushes and non-negligible roughness effects. A modified bearing dynamic analysis model embracing roughness and dynamic characteristics of a non-metal bush is proposed. Based on the model, Reynolds equations of perturbed pressures of water film considering roughness, deformation, and misalignment simultaneously are derived for the first time and solved by coupling the finite difference method and the finite-element method. The results show that dynamic coefficients are enhanced due to roughness when the minimum film thickness ratio exceeds a threshold around 2. The roughness effect is debilitated but the valid range of roughness is extended when bush deformation is considered. Additionally, dynamic coefficients of rougher bearing become obviously smaller than those of smoother bearing as the misalignment angle grows.

Kinematic Nonuniformity of the Rotation of a Toothed Belt Transmission with a Composite Pulley

Existing drive transmissions are analyzed. A toothed belt transmission with a driven pulley that includes an elastic rubber bush is proposed. Formulas are presented for the kinematic nonuniformity of rotation of the driven pulley, its velocity, and its angular displacement as a result of bush deformation.

Thermohydrodynamic performance of water-lubricated thrust bearing of mine high speed rescue pump

In order to meet the requirement of axial force balance of mine rescue pump with high speed and big power, the capacity and reliability of water-lubricated thrust bearing of the pump unit should be improved. This paper presented a study on the capacity of water film and bearing bush deformation of water-lubricated thrust bearing based on the change of temperature in the motor chamber, which is under the actual operation condition of mine high speed rescue pump. In this study, the Reynolds equation was solved by MATLAB to get the thickness of water film, and the deformation of bearing bush was obtained through the joint solution of heat-fluid-solid coupling equation by ANSYS. The results show that the temperatures have little effect on the pressure distribution of water film and the deformation distribution of bearing bush. However, the maximum pressure of water film increases with the temperature. The research of the paper could provide theoretical support and technical guidance for the design of water-lubricated thrust bearings under big power and high speed conditions in the future.

Improvement of lubrication performance of water lubricated polymer bearing via enlarged axial end bearing diameter

Purpose The purpose of this paper is to improve the lubrication performance of a water-lubricated polymer bearing with axial grooves, especially enlarge the minimum film thickness. Design/methodology/approach The bearing diameter is enlarged near the axial ends of the journal, with axial openings of a trumpet shape. A numerical model is developed which considers the proposed trumpet-shaped openings, bush deformation and grooves. The generatrix of the trumpet-shaped opening is assumed to be a paraboloid. Three different variations are covered, and the influences of the trumpet-shaped openings’ parameters on the bearing performance are analyzed. Findings The appropriate trumpet-shaped openings at the axial ends effectively increase the minimum film thickness, and the impact of trumpet-shaped openings on load carrying capacity is very small or even negligible. For the water-lubricated polymer bearing with axial grooves analyzed in this paper, the appropriate trumpet-shaped openings increase the minimum film thickness from 0.53 to 11.14 µm and decrease the load carrying capacity by 2.48 per cent. Practical implications The results of this study can be applied to marine propeller shaft systems and other systems with polymer bearings. Originality/value This paper has presented an approach for significantly increasing the minimum film thickness of a water-lubricated polymer bearing. A study on the performance improvement of water-lubricated polymer bearings with axial grooves is of significant interest to the research community.

Analysis of misaligned water-lubricated polymer bearing with axial grooves

PurposeThe purpose of this paper is to analyze the lubrication behavior of misaligned water-lubricated polymer bearings with axial grooves.Design/methodology/approachA lubrication model considering journal misalignment, bush deformation and grooves is established. In dynamic analyses of shaft systems, bearings are usually simplified as supporting points. Thus, an approach for solving the equivalent supporting point location is presented. The influence of misalignment angle and groove number on film thickness, hydrodynamic pressure distribution, load-carrying capacity and ESP location is investigated.FindingsAs the misalignment angle increases, the location of the maximum pressure and ESP are shifted toward the down-warping end, and the load-carrying capacity of the bearing decreases. In comparison to the nine-groove bearing, the six grooves bearing has a higher load-carrying capacity and the ESP is located closer to the down-warping end for an equivalent misalignment angle.Practical implicationsThe results of this study can be applied to marine propeller shaft systems and other systems with misaligned bearings.Originality/valueA study on the lubrication behavior of misaligned water-lubricated polymer bearings with axial grooves is of significant interest to the research community.

가속도계 및 변위계를 이용한 차량용 고무부시의 변형량 추정 가능성 연구

Ride comfort of a vehicle is often determined by rubber bushes in suspension system. If transmission forces versus deformations across the bushes are available under operational conditions, improvement of the ride comfort could be done with more ease. Recently, the transmission forces are measured using custom-made force transducers inside the links. This study presents a feasibility study on estimation of the rubber bush deformations using vibration signals on the rigid links. Linear variable displacement transducers as well as piezoelectric accelerometers are used to expand frequency range to very low frequency, which cannot be done with accelerometers only. How to estimate the bush deformation from the two vibration signals on the links are presented together with experimental results.

Calculation of Dynamic Stress and Fatigue Strength of Crankshaft with Bush Deformation Included

Dynamic stress and fatigue strength of a crankshaft of diesel engine with four cylinders is studied with consideration of the elastic deformation of bush. Special software ADAMS and ANSYS, assisted by self-designed programs, are adopted to solve the problem. The dynamic pressures of oil film in the bearings are obtained by analysis of dynamics and tribology of the crankshaft-bearing system with consideration of bush deformation. Programming language APDL in ANSYS is adopted to compile program for realizing the force boundary condition, then the dynamic stress on crankshaft journal surfaces is calculated. The fatigue strength of crankshaft is calculated by using damage accumulation theory. It is shown that the minimum thickness of oil film decreases and the maximum pressure of oil film increases to a great extent if the elastic deformation of bush is taken into consideration. The dynamic response and stress of crankshaft vary and the fatigue life of crankshaft decreases by 15.6%.

Experimental determination of the equivalent stress at the frictional surfaces of a slip bearing in a heavily loaded contact

The significant influence of the frictional forces on the bush deformation in a heavily loaded contact is shown. The results of comparative tests are presented. The coefficients for calculating the equivalent stress at the frictional surfaces of a slip bearing are determined.

Study of hole-entry hybrid journal bearing system considering combined influence of thermal and elastic effects

A theoretical model is developed to study the performance of a hole-entry hybrid journal bearing system by considering variation of viscosity due to temperature rise of the lubricant in the analysis. The deformation of bush due to fluid-film pressure and temperature has been considered to establish the modified fluid-film profile. The journal temperature is computed on the basis of the fluid-film temperature. The relevant governing equations have been solved using the finite element method and a suitable iterative technique. The thermoelastohydrostatic performance of an orifice compensated symmetric and asymmetric hole-entry hybrid journal bearing configurations has been studied for the chosen bearing operating and geometric parameters. The results presented in the study indicate that the variation of viscosity due to temperature rise of the lubricant fluid-film have a quite appreciable influence on the static and dynamic performance of a hole-entry hybrid journal bearing system.

Analysis of Cylindrical Journal Bearing With Viscoelastic Bush

Stationarily loaded cylindrical journal bearings with viscoelastic deformable bearing bush is analyzed in this paper. FEM is used to calculate the deformation of bush induced by the pressure of the oil film, which is in its turn influenced by this deformation causing an increment of the oil film thickness. The simultaneous solution of distributions of oil film pressure and thickness is used to obtain the static performances of the bearing. In the analysis of dynamic behavior of the system under small harmonic vibrations, the effect of linear viscoelastic dynamic deformation of bush is taken into consideration. The frequency method is used to obtain the distributions of the derivatives of complex amplitudes of dynamic pressure increment in the oil film with respect to amplitudes of variation of journal eccentricity and attitude angle, and the simultaneously coexisting distributions of derivatives of dynamic deformation amplitudes with respect to the same, wherefrom the linear dynamic coefficients of the viscoelastically supported oil film are obtained. Unbalance response properties and stability threshold speeds of the rotor-bearing system are calculated. Numerical results enable conclusions to be made that suitable viscoelastic property of the bush will effectively improve the dynamic behavior, both in unbalance response and stability.

An Investigation into Plain Journal Bearing Behaviour Including Thermo-Elastic Deformation of the Bush

This paper describes a theoretical investigation into the effect of thermoplastic bush deformation and journal thermal expansion on the behaviour of a cylindrical bore bearing fed by two axial grooves orthogonal to the load line. The main conclusions which follow from this work are that thermoelastic bush deformation is an important factor in predicting bearing operation for a given load duty. It shows that shaft expansion has a very significant influence also.