Needle Roller Bearings Research Articles

Multi-objective optimization of needle roller bearings based on fatigue and wear using evolutionary algorithm

The important considerations for a long-lasting service of needle roller bearings (NRBs) are the long fatigue and wear lives. Keeping in mind these life factors, a design methodology has been proposed to optimize the dynamic capacity ( Cd) and the elasto-hydrodynamic minimum film thickness ( hmin). These are taken for the optimization since the fatigue life is related to Cd and the wear life to hmin. In the optimization problem, a total of seven design variables (which comprises of bearing pitch diameter, roller mean diameter, effective roller length, number of rollers and three other unknown constraint factors), two objectives and 16 constraints are considered. These two objectives are optimized individually (single objective optimization) and simultaneously (multi-objective optimization). The non-linear constrained optimization problem of NRBs has been solved using a multi-objective evolutionary algorithm, called as the Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II). Optimization has been carried out on the set of standard catalogue NRBs. Data obtained from NSGA-II runs of the multi-objective optimization is used to draw the Pareto-optimal fronts (POF). Optimum bearing dimensions are selected by considering the knee point solution on the POF for the comparison with standard bearings. Results showed that optimized bearings got improved lives than standard bearings. Life comparison factors have been calculated and compared with available literatures and are found to be better. Finally, for visualization of optimized NRBs, radial dimensions of three bearings designed by optimizing Cd, hmin and Cd − hmin are shown, for one of the standard NRB. The sensitivity analysis is performed to see the sensitivity of two objectives with design variables.

Optimization of needle roller bearing design using novel hybrid methods

A long fatigue life is one of the most important criteria in the optimum design of needle roller bearings (NRBs). In the present work the dynamic capacity of the bearing is optimized. This non-linear optimization formulation has been solved using the artificial bee colony algorithm (ABCA), differential search algorithm (DSA), grid search method (GSM) and hybrid method (HM, a novel approach of combination of the ABCA/DSA and GSM). A total of four design variables corresponding to bearing geometry are considered, which include the roller diameter, roller length, pitch diameter and number of rollers. Apart from these three more constraint parameters have been optimized. The constraint violation study is carried out to prioritize the constraints. The sensitivity analysis is carried out to see the effect of tolerance on design variables on the dynamic capacity. The dynamic capacity of optimized bearings is found to have an upper hand from those specified in bearing catalogs.

Dynamic Analysis of Needle Roller Bearings on Torque Loss

Dynamic Analysis of Needle Roller Bearings on Torque Loss

Dynamic Analysis of Needle Roller Bearings on Torque Loss

Dynamic Analysis of Needle Roller Bearings on Torque Loss

Frictional power loss in solid‐grease‐lubricated needle roller bearing

ABSTRACTThe use of solid grease as a lubricant, in comparison with standard grease or oil, is a pre‐requisite when needle roller bearings undergo a high‐speed oscillating motion and when access to the bearing is difficult for maintenance purposes. This paper examines the frictional power loss of a solid‐grease‐lubricated needle roller bearing. First set of measurement result reveals that the test bearing has higher frictional power loss as compared with other bearings with conventional lubrications, due to the high viscosity of the solid grease. Furthermore, measurements are compared with the Palmgren and SKF models. For improving these models, the parameters of the models are updated on the basis of the measurement data. A second set of measurement result shows that the use of oil (kept at higher temperature) in addition to solid grease significantly reduces the frictional power loss. The reduction is due to the decrease in operational viscosity of the solid grease. Copyright © 2012 John Wiley & Sons, Ltd.

749 針状ころ軸受のトルク損失に関する動的挙動解析

This study concentrates on torque loss of needle roller bearings used in a planetary gear set. Dynamic analysis is conducted to investigate mechanisms of friction loss by a multibody dynamics (MBD) model, which is developed to consider dynamic effects on the planetary gear and contact conditions. Contact analysis of needle rollers with other parts utilizes the discrete ball model to obtain the distribution of contact points and to decrease computational cost. The sliding friction coefficient is defined by experimental results that evaluate the relationships between the thrust force and the skew angle of the needle rollers. The MBD analysis evaluates bearing clearances between the needle rollers and other parts in the radial and circumferential directions. It is found that the clearances between the needle rollers and the cage in the circumferential direction are a dominant factor in friction loss. Moreover, numerical results confirm that the skew angle of the needle roller with respect to its rotation axis has the most significant effect on the friction loss of the bearing. The skew of the needle roller causes thrust force that pushes the pinion gear onto the side washer that supports the axial motion of the pinion gear. Finally, this study suggests an appropriate clearance between the needle rollers and the cage to reduce the skew angle of the needle rollers and the friction loss between the pinion gear and the thrust side contact. The circumferential clearance should be designed as small as possible.

Design and control of a directly-driven bond head for thermosonic bonding

This article presents a high-acceleration rotary bond head to improve the efficiency and precision of thermosonic bonding. The bond head is direct driven by a rotary voice coil actuator, and needle roller bearings are adopted as the rotary connection parts. Using the finite-element analysis and experiment tests, the dynamic characteristics of the bond head were investigated. The results indicate that the vibrations of the bond head have negative influences on the bonding process and the ultrasonic transducer system. They can reduce the efficiency of the ultrasonic energy transmission and even result in the bonder working abnormally. To avoid these vibration modes, high-frequency harmonic components of the driving signals were eliminated by adding a notch filter to the control system. Considering the remnant vibrations during high-frequency starts and stops, friction compensation and proportion integration differentiation (PID) feedback control with anti-windup correction were adopted. The controller was designed and co-simulated by using MATLAB and MSC.ADAMS software. The co-simulation and experiment results show that the bond head provides for good performances.

Simplified modeling for needle roller bearings to analyze engineering structures by FEM

The rolling bearings are frequently applied elements of the mechanical structures. During finite element modeling of rolling bearing supported structures to define the adequate accuracy of bearing rigidity behavior enlarge immensely the FE model size and the related calculation time. So it is an understandable effort to use simplified substituting model for rolling bearing which carries the bearing rigidity character and does not make an unnecessary complicated structural model. In this paper the authors present a substituting technique for needle roller bearing.

Thrust Force Analysis of Tripod Constant Velocity Joint Using Multibody Model

A tripod constant velocity joint is used in the driveshaft of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. To analyze the thrust force, a detailed model is constructed based on a multibody dynamics approach. This model includes all principal parts of the joint defined as rigid bodies and all force elements of contact and friction acting among these parts. This model utilizes a new contact modeling method of needle roller bearings for more precise and faster computation. By comparing computational and experimental results, the appropriateness of this model is verified and the principal factors inducing the second and third rotating order components of the thrust force are clarified. This paper also describes the influence of skewed needle rollers on the thrust force and evaluates the contribution of friction forces at each contact region to the thrust force.

An Ambulatory Pulmonary and Right Heart Assist Device (OxyRVAD) in an Ovine Survival Model

To develop ambulatory total respiratory and right heart assistance for up to 4 weeks as a bridge to lung transplantation, we coupled a compact gas exchange device with a right ventricular assist device (RVAD), a compact rotary blood pump, to create an "OxyRVAD." Our ambulatory OxyRVAD includes a portable (4 x 4 x 7-cm) centrifugal pump with heparin saline-purged needle roller bearings and an ultra-low-resistant gas exchange device (BioLung, MC3, Ann Arbor, MI). In 6 anesthetized sheep, the main pulmonary artery (PA) and right atrium (RA) were exposed through a left fourth intercostal thoracotomy. A 12-mm outer diameter vascular graft was anastomosed (end-to-side) to the main PA, and a VAD atrial cannula was placed into RA through the RA appendage. The pump and gas exchange device were interposed in circuit for RA-PA support. All 6 sheep survived OxyRVAD insertion. Four sheep survived the 5-day experiment. One was euthanized at 48 hours owing to pump electrical failure (wiring) and another at 72 hours owing to pump bearing failure (broken heparin purge line). One sheep needed replacement of a BioLung due to internal thrombi. OxyRVAD flow was stable (range, 3.57-4.30 liters/min). Carbon dioxide removal was constant during experiment (range, 88.35 +/- 6.12 ml/min at onset to 141.38 +/- 5.48 ml/min at the 96th hour). Oxygen transfer decreased from 161.8 +/- 8.8 to 79.7 +/- 31.4 ml/min at the 96th hour (p = 0.045). Our ambulatory OxyRVAD provided total assistance of right heart and lungs in normal awake sheep for up to 5 days.

Super low friction of DLC applied to engine cam follower lubricated with ester-containing oil

This paper presents a material combination that reduces the friction coefficient markedly to a superlow friction regime (below 0.01) under boundary lubrication. A state approaching superlubricity was obtained by sliding hardened steel pins on a hydrogen-free diamond-like carbon (DLC) film (ta-C) lubricated with a poly-alpha-olefin (PAO) oil containing 1 mass% of an ester additive. This ta-C/steel material combination showed a superlow friction coefficient of 0.006 at a sliding speed of 0.1 m/s. A hydrogencontaining DLC coating/steel combination also showed a lower friction coefficient in air than a steel/steel combination, 0.1 vs. 0.8, but no large reduction was observed when the sliding surfaces were lubricated with ordinary 5W-30 engine oil and the PAO oil containing an ester additive. The friction coefficient of the hydrogen containing DLC/steel combination lubricated with the PAO containing an ester additive was above 0.05. On the other hand, the superlow friction performance demonstrates that the rolling contact friction level of needle roller bearings can be obtained in sliding contact under a boundary lubrication condition. It is planned to apply this advanced DLC coating technology to valve lifters lubricated with a newly formulated engine oil in actual mass-produced gasoline engines. A larger friction reduction of more than 45% is expected to be obtained at an engine speed of 2000 rpm.

THE PROTOTYPE OF TRANS-VENTRICULAR LVAD WITH ROLLING BEARINGS AND A PURGE SYSTEM: TOWARD DURABILITY AND PERFORMANCE

Purpose: To develop a simple plug-and-play Transventricular/transAortic valve LVAD (TA-LVAD) for acute left heart dysfunction designed to just plug into the cardiac apex via a small left thoracotomy to achieve immediate total left ventricular (LV) support. Methods: The LVAD is composed of a motor and an impeller pump within a custom cannula designed to be placed transapical across the LV chamber, through the aortic valve, into the aortic root. The motor has a motor coil with iron core and a rotor with a 4-pole magnet. The pump has a low impact three turbine impeller with an outflow guide vane. The motor is supported by 8 needle roller bearings in each end of the rotor to reduce friction and is purged by a heparin saline infusion to prevent bearing thrombosis. The pump prototype was tested in saline with the outlet connected to 3/8” tubing for flow and pressure head measurements. The preload of the pump was kept at zero mmHg. The pump was operated at 12500, 15000 and 17500 rpm to determine pressure and flow curves. Results: The pump as fabricated had a length of 11.5 cm and weight of 53 grams. The performance property diagram shows: the prototype can pump 4 l/min at 15000 rpm and 9 l/min at 17500 rpm, against 100 mmHg afterload. Conclusion: Our current prototype with a length of 11.5 cm and diameter of 13 mm achieves total left ventricular support and is designed to be easily inserted transapically.

114 スラスト針状ころ軸受におけるころの挙動(計測・設計)

114 スラスト針状ころ軸受におけるころの挙動(計測・設計)

Evaluation of the life margin of oscillating needle roller bearings: Rumbarger, J. H. Transactions of the American Society of Lubrication Engineers, Vol 12, No 2 (April 1969) pp 162–170

Evaluation of the life margin of oscillating needle roller bearings: Rumbarger, J. H. Transactions of the American Society of Lubrication Engineers, Vol 12, No 2 (April 1969) pp 162–170

Paper 23. Needle Bearings and their Applications in Automotive Industries

The author describes briefly the development of needle roller bearings since 1922. Various types of modern bearings are described and illustrated and many of the examples illustrate up-to-date applications in driveline components.

Evaluation of the Life Margin of Oscillating Needle Roller Bearings

The life-margin of oscillating caged needle roller bearings is determined in an explicit non-statistical manner. Life-margin is the difference between the first macroscopic evidence of spalling fatigue and the end of useful bearing life. The bearings were life tested under service conditions closely duplicating those in helicopter rotor vertical and horizontal hinge pin locations. Test results are presented for nineteen bearings lubricated with MIL-L-7808 oil. The use of magnetic chip-detectors and spectrometric oil analysis as failure indicating devices are discussed. Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference hold in Atlantic City, New Jersey, October 8–10. 1968.

Dynamic Capacity of Oscillating Rolling Element Bearings

The results of life tests of 388 caged, needle-roller bearings under combinations of load, speed, and amplitude of oscillation are analyzed with Weibull statistics. The rolling bearing theory of Lundberg and Palmgren is extended to cover oscillating roller bearings and is favorably compared with the life tests. A formula for basic dynamic capacity in oscillation is developed for amplitudes of oscillation which are less than the critical amplitude. Capacity formulas are also presented for both ball and roller bearings for any amplitude of oscillation.

High-Pressure Gear Pumps

Gear pumps have been used in very large numbers for the various hydraulic services of war aircraft. For the higher pressures the main problems have been in connexion with the load on the journal bearings, with wear, and with the reduction in volumetric efficiency caused by internal leakage. The journal loads are affected by the number of teeth and by the ratio of width to diameter of the gears. With high pressures it is difficult to accommodate standard ball or roller races on account of their diameter: designs are illustrated using a combination of standard races and special needle roller bearings. Small amounts of wear cause comparatively large reductions in volumetric efficiency. Major causes of wear are rubbing on the gear end faces and solid matter in suspension in the liquid and methods of dealing with these are discussed. The percentage slip due to internal leakage varies inversely as the factor (r.p.m. × viscosity). At low speeds and with low-viscosity liquids, internal leakage often limits the pressure at which the pump can be used. Multistage pumps reduce the leakage and have been used extensively for undercarriage operation. Internal leakage becomes relatively less as the size of the pump is increased and the paper gives a graph, showing the relationship between the limit of pressure at which 80 per cent volumetric efficiency is possible, the capacity and rotational speed of the pump, and the viscosity of the liquid. Aircraft pumps generally use gears with involute teeth: ports in the end covers of the casing are used to prevent excessive pressure in the liquid trapped between the teeth. Low- and high-leakage conditions call for difficult arrangements of ports, and this involves differing displacements and variations in flow velocity.

A New Needle Bearing

ONE of the objections attendant on the use of needle roller bearings, as illustrated in Fig. 1, has been overcome by the introduction of needle rollers having trunnion instead of spherical ends. In the type shown in Fig. 1, without adding considerably to the cost of the bearing, it is only with difficulty that the rollers can be kept in position during the process of fitting, whereas with the design illustrated in Fig. 2, by the employment of rollers having trunnion ends, they can be readily retained in the outer ring by means of pressings fitted into the bore of the shoulders, thus enabling the outer ring and rollers to be handled as a single unit during fitting.