scholarly journals A new approach for the load calculation of the most loaded rolling element for the rolling bearing with internal radial clearance - The case study

2020 ◽  
Author(s):  
Radoslav Tomović
Keyword(s):  
Roller Bearing ◽  
Rolling Bearing ◽  
Radial Clearance ◽  
Practical Application ◽  
New Approach ◽  
Load Factors ◽  
Proposed Model ◽  
Rolling Element ◽  
Load Calculation

Abstract In this paper is presented a case study which has the goal to show the benefits of the application of a new approach for the calculation of load of the most loaded rolling element at the rolling bearing with the internal radial clearance. The calculation is based on the so-called load factors. By multiplication load factors with the value of the external radial load, the load which is transferred by the most loaded rolling element of the bearing is obtained. The case study is made for two types of bearings, the ball, and roller bearing. Obtained results were compared with the results obtained based on the calculation using some of the most commonly used methods so far. The analysis showed greater precision of the considered model with the same or much simpler application. For this reason, the proposed model is considered very suitable for practical application.

scholarly journals Load Calculation of the Most Loaded Rolling Element for a Rolling Bearing with Internal Radial Clearance

2020 ◽  
Vol 10 (19) ◽  
pp. 6934
Author(s):  
Radoslav Tomović
Keyword(s):  
Ball Bearing ◽  
Roller Bearing ◽  
Rolling Bearing ◽  
Radial Clearance ◽  
Load Factor ◽  
New Model ◽  
Load Factors ◽  
Rolling Element ◽  
Load Calculation ◽  
Rolling Elements

This paper presents a new model for calculation of load for the most loaded rolling element in a rolling bearing with internal radial clearance. The calculation is based on a so-called load factor. By multiplying this factor by the value of the external radial load, the load transferred by the most loaded rolling element of the bearing is obtained. The values of the load factor are shown in the tables and diagrams, which makes the model very suitable for practical use. The load factors are shown for a ball bearing as well as for a roller bearing. The model considers two support positions of the inner ring on an even and odd number of rolling elements. The new model was compared with the most commonly used models up to now. The results showed greater accuracy of the studied model.

scholarly journals A New Approach to Inform Restoration and Management Decisions for Sustainable Apiculture

2021 ◽  
Vol 13 (11) ◽  
pp. 6109
Author(s):  
Joanne Lee Picknoll ◽  
Pieter Poot ◽  
Michael Renton
Keyword(s):  
Floral Resources ◽  
Pollination Services ◽  
New Approach ◽  
Honey Production ◽  
Proposed Model ◽  
Colony Loss ◽  
Supply Potential ◽  
Australian Case ◽  
Stocking Rates

Habitat loss has reduced the available resources for apiarists and is a key driver of poor colony health, colony loss, and reduced honey yields. The biggest challenge for apiarists in the future will be meeting increasing demands for pollination services, honey, and other bee products with limited resources. Targeted landscape restoration focusing on high-value or high-yielding forage could ensure adequate floral resources are available to sustain the growing industry. Tools are currently needed to evaluate the likely productivity of potential sites for restoration and inform decisions about plant selections and arrangements and hive stocking rates, movements, and placements. We propose a new approach for designing sites for apiculture, centred on a model of honey production that predicts how changes to plant and hive decisions affect the resource supply, potential for bees to collect resources, consumption of resources by the colonies, and subsequently, amount of honey that may be produced. The proposed model is discussed with reference to existing models, and data input requirements are discussed with reference to an Australian case study area. We conclude that no existing model exactly meets the requirements of our proposed approach, but components of several existing models could be combined to achieve these needs.

Investigation on the skidding dynamic response of rolling bearing with local defect under elastohydrodynamic lubrication

2019 ◽  
Vol 20 (6) ◽  
pp. 615 ◽  
Author(s):  
Jianxiong Kang ◽  
Yanjun Lu ◽  
Yongfang Zhang ◽  
Cheng Liu ◽  
Sha Li ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Interaction Force ◽  
Local Defect ◽  
Proposed Model ◽  
Significant Difference ◽  
Frequency Domains ◽  
Rolling Element ◽  
Time And Frequency Domains

The rolling element skidding may lead to the failure of the rolling bearing. The skidding characteristics can be effectively analyzed by using dynamic response of the rolling bearing. A dynamic model is established to investigate the vibration response of the rolling bearing with local defect on inner/outer race in this paper. In the proposed model, the rolling element skidding, contact stiffness and displacement, the interaction force between ball and race, the interaction force between cage and race, elastohydrodynamic lubrication are taken into consideration. The dynamic responses of the rolling bearing with the rolling element skidding are solved by the proposed model in the time and frequency domains. The effects of defect size, rotational speed, external load, and compound factors on skidding characteristics are investigated. The proposed model is verified by the experiments. The results show that the rolling element skidding leads to the significant difference of dynamic characteristics in the time and frequency domains, which aggravates the failure of the rolling bearings.

Comparison of Advanced Signal-Processing Methods for Roller Bearing Faults Detection

2012 ◽  
Vol 19 (4) ◽  
pp. 715-726 ◽  
Author(s):  
Jacek Urbanek ◽  
Tomasz Barszcz ◽  
Tadeusz Uhl
Keyword(s):  
Wind Turbines ◽  
Roller Bearing ◽  
Rolling Element Bearing ◽  
Monitoring Methods ◽  
Operational Conditions ◽  
Rolling Element ◽  
Fast Development ◽  
Element Bearing ◽  
Signal Processing Methods

Abstract Wind turbines are nowadays one of the most promising energy sources. Every year, the amount of energy produced from the wind grows steadily. Investors demand turbine manufacturers to produce bigger, more efficient and robust units. These requirements resulted in fast development of condition-monitoring methods. However, significant sizes and varying operational conditions can make diagnostics of the wind turbines very challenging. The paper shows the case study of a wind turbine that had suffered a serious rolling element bearing (REB) fault. The authors compare several methods for early detection of symptoms of the failure. The paper compares standard methods based on spectral analysis and a number of novel methods based on narrowband envelope analysis, kurtosis and cyclostationarity approach. The very important problem of proper configuration of the methods is addressed as well. It is well known that every method requires setting of several parameters. In the industrial practice, configuration should be as standard and simple as possible. The paper discusses configuration parameters of investigated methods and their sensitivity to configuration uncertainties

Analysis of an Improved Planetary Gear-Transmission Bearing

1964 ◽  
Vol 86 (3) ◽  
pp. 457-461 ◽  
Author(s):  
T. A. Harris ◽  
J. L. Broschard
Keyword(s):  
Fatigue Life ◽  
Gear Tooth ◽  
Roller Bearing ◽  
Planetary Gear ◽  
Major Axis ◽  
Rolling Bearing ◽  
Load Application ◽  
Outer Ring ◽  
Rolling Element ◽  
Oriented Parallel

In planetary-gear transmissions, especially for aircraft applications, the planet gears are frequently made integral with the outer rings of rolling bearings. Thus the outer ring of the rolling bearing is subjected to the tangential, radial, and moment loading attendant to spur gears. If the outer ring of the bearing is relatively thin, the distortion induced therein by the gear forces alters the distribution of load from that of a roller bearing with a rigid outer ring, causing a significant reduction in the bearing fatigue life. Since the maximum rolling-element loads in the bearing occur in close angular proximity of the points of load application, it would appear that the magnitude of these rolling-element loads may be diminished and fatigue life subsequently increased by selectively applying clearance between rolling elements and raceway at the points of load application. In fact, theoretical analysis of a planetary-gear bearing having an out-of-round inner ring, wherein the major axis is oriented parallel to the tangential gear-tooth load, indicates that a condition of optimum clearance and out-of-round exists with respect to bearing fatigue life. An increase in fatigue life of approximately 40 percent is indicated with only a nominal amount of out-of-round.

Adopting trust and assurance as indicators for the reassignment of responsibilities in multi-agent systems

2015 ◽  
Vol 30 (2) ◽  
pp. 187-200 ◽  
Author(s):  
Benjamin Gâteau ◽  
Moussa Ouedraogo ◽  
Christophe Feltus ◽  
Guy Guemkam ◽  
Grégoire Danoy ◽  
...  
Keyword(s):  
Distributed Systems ◽  
Weather Station ◽  
Multi Agent Systems ◽  
New Approach ◽  
Agent Systems ◽  
Trust Level ◽  
Proposed Model ◽  
Selection Parameter ◽  
Multi Agent

AbstractMulti-agent systems have been widely used in the literature, including for the monitoring of distributed systems. However, one of the unresolved issues in this technology remains in the reassignment of the responsibilities of monitoring agents when some of them become unable to meet their obligations. This paper proposes a new approach for solving this problem based on (a) the gathering of evidence on whether the agent can or cannot fulfil the tasks it has been assigned and (b) the reassignment of the task to alternative agents using their trust level as a selection parameter. A weather station case study is proposed as an instantiation of the proposed model.

scholarly journals The Concept of the Geotourism Potential and Its Practical Application: A Case Study of the Prządki (the Spinners) Nature Reserve in the Carpathians, Poland

Resources ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 145
Author(s):  
Ewa Welc ◽  
Krzysztof Miśkiewicz
Keyword(s):  
Nature Reserve ◽  
Field Research ◽  
Practical Application ◽  
New Approach ◽  
Cultural Aspects ◽  
Tourist Infrastructure ◽  
Definition Of ◽  
Educational Potential ◽  
First Time

This paper reviews the recent use of the term “geotourism potential” in the scientific literature and proposes a new approach to the concept of geotourism potential. The concept assumes that every geotourism object has the well-developed features that allow one to learn and understand the object’s structure, genesis and properties. A method for the application of this concept to any geotourism object is proposed. The procedure and guidelines for the compilation of geotourism potential are applied on the example—the Prządki Nature Reserve in the Flysch Carpathians, Poland. Based on the field research, the research results of other scientists, and the internationally accepted definitions of terms connected with geotourism, a definition of geotourism potential is presented for the first time in academic literature. The main results emphasize that only clearly exposed features within the geotourism object relate to geotourism potential, while educational potential and tourist infrastructure are not to be identified with this potential. The inclusion of a new procedure for use in geotourism research provides a comprehensive approach to the inventory of geotourism objects and the educational use of abiotic elements of nature, as well as biotic and cultural aspects related to geoheritage. The presented model has practical application in the design of geoeducational materials.

A Series of New Nonlinear Dynamic Equations of Rolling Element Bearing Systems

2010 ◽  
Vol 118-120 ◽  
pp. 896-901
Author(s):  
Dong Xu ◽  
Yong Cheng Xu ◽  
Xun Chen ◽  
Yong Min Yang ◽  
Xing Lin Li
Keyword(s):  
Rolling Bearing ◽  
Rolling Element Bearing ◽  
Evolution Process ◽  
Radial Clearance ◽  
Rolling Bearings ◽  
Nonlinear Dynamic Equations ◽  
Rolling Element ◽  
Element Bearing ◽  
Fault Evolution ◽  
Additional Equation

As one of the key parts of rotating machinery, rolling bearing is the primary fault source, therefore it is urgent to research failure mechanism and its evolution process. First, the number of laden rollers of rolling bearings in different states without radial clearance and preload is summed up, and then nonlinear analytical equations and an additional equation are proposed. To some extent it will be helpful for researching the fault evolution process of rolling element bearings combined with fatigue theories. Further they will conduce to analyze and predict the remaining life of ball bearings.

scholarly journals 5-DOF Dynamic Modeling of Rolling Bearing with Local Defect considering Comprehensive Stiffness under Isothermal Elastohydrodynamic Lubrication

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Pengfei Yan ◽  
Changfeng Yan ◽  
Kai Wang ◽  
Fengtao Wang ◽  
Lixiao Wu
Keyword(s):  
Film Thickness ◽  
Life Prediction ◽  
High Speed ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Radial Clearance ◽  
Local Defect ◽  
Oil Film ◽  
Rolling Element ◽  
Film Stiffness

The sliding of the rolling element in the load zone would cause the bearing’s wear and failure at high speed under elastohydrodynamic lubrication (EHL) condition. Aiming at this phenomenon, considering lubrication oil film, time-varying displacement, radial clearance, and comprehensive stiffness, a five degree-of-freedom (DOF) dynamic model of rolling bearing with local defect is proposed based on isothermal EHL and which is validated by experimental data. The variation of oil film stiffness, comprehensive stiffness, and vibration characteristics of rolling bearing is studied under different speeds and loads. The results show that the lubricating oils with different viscosities have a certain influence on the bearing oil film thickness and comprehensive stiffness. As the load increases, the oil film stiffness and comprehensive stiffness would increase, and the oil film thickness would decrease. And as the tangential speed increases, the oil film stiffness would increase, and the oil film thickness and comprehensive stiffness would decrease. The vibration amplitude of the rolling bearing is enhanced with the increase of the rotation speed and the radial load. This model is helpful for the optimization, the correct use of lubricants, and life prediction of rolling bearing.

Modeling of Crossed Roller Bearings Considering Roller Roundness Deformation

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Van-Canh Tong ◽  
Eui-Wook Jung ◽  
Seong-Wook Hong
Keyword(s):  
Degrees Of Freedom ◽  
Unit Length ◽  
Roller Bearing ◽  
Rolling Element Bearing ◽  
Flat Surfaces ◽  
Roller Bearings ◽  
Proposed Model ◽  
Rolling Element ◽  
Inertial Loading ◽  
Speed Effect

Abstract This paper presents a quasi-static five degrees-of-freedom model of crossed roller bearings that considers roller roundness deformation. The existing models of rolling element bearing do not account for ball and/or roller roundness deformation. However, in the case of crossed roller bearing, roundness deformation of rollers can be significant because of high contact load per unit length of rollers. In this paper, the roller roundness deformation was included by using a formulation of the roller as a cylinder under compression by two flat surfaces. The inertial loading due to rotational speed effect was considered by including the centrifugal force and gyroscopic moment of rollers. Experiments were performed to validate the proposed model, and calculated and measured axial displacements of the bearing under axial loads yielded a good correlation. Extensive simulations were conducted to show the importance of roller roundness deformation and the applicability of the proposed model. The developed model for crossed roller bearing will be useful for the design and extensive analysis of crossed roller bearings.

Sign in / Sign up

Export Citation Format

Share Document