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Open Access
Article
Publication date: 29 May 2020

Li Cui

Bearings in electric machines often work in high speed, light load and vibration load conditions. The purpose of this paper is to find a new fatigue damage accumulation rating…

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Abstract

Purpose

Bearings in electric machines often work in high speed, light load and vibration load conditions. The purpose of this paper is to find a new fatigue damage accumulation rating life model of ball bearings, which is expected for calculating fatigue life of ball bearings more accurately under vibration load, especially in high speed and light load conditions.

Design/methodology/approach

A new fatigue damage accumulation rating life model of ball bearings considering time-varying vibration load is proposed. Vibration equations of rotor-bearing system are constructed and solved by Runge–Kutta method. The modified rating life and modified reference rating life model under vibration load is also proposed. Contrast of the three fatigue life models and the influence of dynamic balance level, rotating speed, preload of ball bearings on bearing’s fatigue life are analyzed.

Findings

To calculate fatigue rating life of ball bearings more accurately under vibration load, especially in high speed and light load conditions, the fatigue damage accumulation rating life model should be considered. The optimum preload has an obvious influence on fatigue rating life.

Originality/value

This paper used analytical method and model that is helpful for design of steel ball bearing in high speed, light load and vibration load conditions.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2019-0180/

Details

Industrial Lubrication and Tribology, vol. 72 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 24 November 2020

Pingping He, Feng Gao, Yan Li, Wenwu Wu and Dongya Zhang

The purpose of this paper is to research on optimization of spindle bearing preload based on efficiency coefficient method and provide theoretical guidance for variable preload of…

180

Abstract

Purpose

The purpose of this paper is to research on optimization of spindle bearing preload based on efficiency coefficient method and provide theoretical guidance for variable preload of intelligent spindle.

Design/methodology/approach

Based on an established thermo-mechanical coupling model of angular contact ball bearing with fix-position preload, temperature rise and axial stiffness of the bearing at different speeds and preload are analyzed, and life of the bearing is estimated by the improved L-P theory. The bearing temperature rise, axial stiffness and life data are standardized, and the preload is optimized by the efficiency coefficient method according to the requirements of operating conditions.

Findings

The optimized preload meets comprehensive requirements of the bearing temperature rise, axial stiffness and life under different operating conditions.

Originality/value

In the past studies, it is rarely reported that temperature rise, stiffness and life of the bearing under thermo-mechanical coupling effect are used as objective functions to optimize preload at different speeds.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2020-0205/

Details

Industrial Lubrication and Tribology, vol. 73 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 24 October 2018

Ayush Jain, Abhishek Singh and Arendra Pal Singh

This paper aims to study the sliding wear and coefficient of friction (COF) using “ball on disc” tribometer. Discs of bearing steel were subjected to different tribological…

Abstract

Purpose

This paper aims to study the sliding wear and coefficient of friction (COF) using “ball on disc” tribometer. Discs of bearing steel were subjected to different tribological parameters such as heat treatment (through hardening and case hardening), sliding speed, sliding distance and micro-geometry of the functional ball and disc point contact. Results obtained from tribometer were correlated with the preload loss in tapered roller bearing. Preload loss is subjected to wear rate pattern with respect to the internal geometry and micro-geometry of functional surfaces of the tapered roller bearing, caused by internal resistance between roller large ends sliding against cone supporting face. This confirms the optimum geometry and physical/mechanical property of the tapered roller bearing, which makes the use of these bearings under the demanding application in the automotive industry such as differential gears and installation of pinions of differential gears in power transmissions or wheels.

Design/methodology/approach

The paper opted for an exploratory study using the design of experiments with full factorial method. The approach was to do ball on disc sliding wear test and correlate that sliding wear with preload loss in tapered roller bearing.

Findings

The paper provides the limit of preload loss in tapered roller bearing.

Research limitations/implications

Because of the chosen research approach, the research lacks the effect of environmental conditions such as temperature and relative humidity and lube film thickness effect on wear test. It also lacks the validation part with actual preload loss on tapered roller bearings. Above work is included in future scope of work.

Practical implications

This paper includes the recommendation for surface parameters which can increase the bearing life by reducing the preload loss in tapered roller bearing.

Social implications

This paper includes the recommendation for surface parameters for bearing manufacturing industries.

Originality/value

This paper provides the relation between sliding wear and preload loss in tapered roller bearing.

Details

Industrial Lubrication and Tribology, vol. 71 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 March 2006

Peihua Zhang, Xin Liu, Lijing Wang and Xungai Wang

To examine a simple testing method of measuring the force to pull a fabric through a series of parallel pins to determine the fabric softness property.

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Abstract

Purpose

To examine a simple testing method of measuring the force to pull a fabric through a series of parallel pins to determine the fabric softness property.

Design/methodology/approach

A testing system was setup for fabric pulling force measurements and the testing parameters were experimentally determined. The specific pulling forces were compared with the fabric assurance by simple testing (FAST) parameters and subjective softness ranking. Their correlations were also statistically analyzed.

Findings

The fabric pulling force reflects the physical and surface properties of the fabrics measured by the FAST instrument and its ability to rank fabric softness appears to be close to the human hand response on fabric softness. The pulling force method can also distinguish the difference of fabrics knitted with different wool fiber contents.

Research limitations/implications

Only 21 woven and three knitted fabrics were used for this investigation. More fabrics with different structures and finishes may be evaluated before the testing method can be put in practice.

Practical implications

The testing method could be used for objective assessment of fabric softness.

Originality/value

The testing method reported in this paper is a new concept in fabric softness measurement. It can provide objective specifications for fabric softness, thus should be valuable to fabric community.

Details

International Journal of Clothing Science and Technology, vol. 18 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 3 April 2019

Shengli Tian, Xiaoan Chen, Tianchi Chen and Ye He

The purpose of this study is to investigate accurate and effective experimental methods for measuring the frictional loss of bearings (FLB) in mechanical systems and to measure…

Abstract

Purpose

The purpose of this study is to investigate accurate and effective experimental methods for measuring the frictional loss of bearings (FLB) in mechanical systems and to measure the effect of various operating parameters on the frictional loss of high-speed mechanical systems.

Design/methodology/approach

Two novel methods were studied in this paper to measure the FLB: the free-deceleration method and the energy-balance method. A special high-speed motorised spindle and a friction loss test rig were designed and built to measure the effects of rotational speed, lubrication, preload and operating temperature on the FLB.

Findings

The experimental results showed that the frictional torque of bearings increases initially but then decreases with an increase in rotational speed. Similarly, the FLB decreases initially and then increases with an increase in temperature because of the influence of the viscosity–temperature relationship of the lubricant and the thermomechanical coupling factor. The optimal lubricant flow was determined, and the effectiveness of a novel preload online adjusting device was verified through experiments.

Originality/value

The research results of this paper provide the basis and methods for the measurement, reduction and prediction of the FLB in mechanical systems.

Details

Industrial Lubrication and Tribology, vol. 71 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 6 August 2018

Kuldeep Verma and R.M. Belokar

This paper aims to investigate the performance and positioning accuracy of computer numerical controlled (CNC) feed drive system using a ball screw-based pre-loading impact factor.

Abstract

Purpose

This paper aims to investigate the performance and positioning accuracy of computer numerical controlled (CNC) feed drive system using a ball screw-based pre-loading impact factor.

Design/methodology/approach

Initially, axial displacement of support bearings has been computed in relation to the different preload values. Among the computed values, a basic rule equation has been developed for the calculation of elongation in the bearings. The value of displacements computed from the developed equation has been considered as a pre-loading value, and its behavior on the feed drive system has been analyzed.

Findings

The elongation of bearings impacts the positioning accuracy and repeatability of the feed drive system and of CNC machines. Next, an analytical model for the rigorous assessment of CNC feed drive system has been designed and developed. The positioning accuracy of CNC machine in relation with different pre-loading values has been analyzed.

Practical implications

The results obtained from these investigations enhance the positioning accuracy of CNC machining centers. The optimum pre-loading value has been analyzed among the available ranges, and it has been proposed that optimal results have been achieved at 5 per cent of dynamic load rating.

Originality/value

This paper proposes improved explorations toward the performance of the CNC machines by optimizing the positioning accuracy through pre-loading. Finally, analytical estimations have been carried out to prove the validity of the proposal.

Details

Assembly Automation, vol. 38 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 8 May 2018

Runlin Chen, Jianlei Wang, XiaoYang Yuan, Longlong Li and Yahui Cui

To meet the high stiffness requirement of bearings used in high-precision spindles, this paper aims to propose a novel kind of bearing composited by hydrostatic cavities and…

Abstract

Purpose

To meet the high stiffness requirement of bearings used in high-precision spindles, this paper aims to propose a novel kind of bearing composited by hydrostatic cavities and tilting pads with preload.

Design/methodology/approach

Cavities are cut on the oil seal surface of a hybrid bearing, in which the tilting pads are set up. The load of the bearing is carried by the hydrostatic cavities and tilting pads. The structural features of this compound bearing and the controlling variables of the main stiffness coefficient are presented. Two basic design principles are proposed on the basis of equal machining clearance (EMC) and equal installation clearance (EIC).

Findings

The theoretical analysis indicates that the stiffness of compound bearings under the EMC condition increases to infinity monotonously when the preload coefficient of the tilting pad tends to 1, while the stiffness under the EIC condition has a peak value. Therefore, a synthetic design principle is proposed by synthetically using the above-mentioned two principles. The applicable range of the three principles is discussed through an example.

Originality/value

The study about technological combination of hydrostatic cavity and tilting pad in this paper can provide suggestions for the design of a high-stiffness bearing in a precision spindle.

Details

Industrial Lubrication and Tribology, vol. 70 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 March 2013

M. Nekoeimehr, A.D. Rahmatabadi and R. Rashidi

The purpose of this paper is to analyse the static performance characteristics of lobe journal bearings lubricated with a micropolar fluid, considering effect of non‐circularity…

Abstract

Purpose

The purpose of this paper is to analyse the static performance characteristics of lobe journal bearings lubricated with a micropolar fluid, considering effect of non‐circularity. Number of lobes and their preload value are the non‐circularity parameters considered in the present study. The bearings undertaken for the investigation are two, three and four‐lobe symmetric journal bearings with finite width.

Design/methodology/approach

For this purpose, modified form of Reynolds equation is derived, based on Eringen's micropolar fluid theory and it is solved numerically using finite element method (FEM). The effect of the non‐circularity parameters of bearings on the steady‐state performance characteristics such as load carrying capacity, attitude angle, coefficient of friction and side leakage flow are presented and discussed.

Findings

The results show that the number of lobes and their preload value can influence the performance of lobe bearings. It is seen that, in order to provide certain improvement over simple cylindrical bearings, the non‐circularity parameters of lobe bearings must be chosen correctly. There is no single optimum profile for multi‐lobe bearing application.

Originality/value

Lobe bearings, compared with simple circular bearings, offer several geometric parameters to designers. These parameters must be chosen correctly, so that the requirements of a specific application can be fulfilled.

Details

Industrial Lubrication and Tribology, vol. 65 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 8 March 2011

Hamit Saruhan

This paper aims to utilize an evolutionary algorithm as an optimization technique to solve design optimization of a pivoted‐pad journal bearing performance characteristics…

Abstract

Purpose

This paper aims to utilize an evolutionary algorithm as an optimization technique to solve design optimization of a pivoted‐pad journal bearing performance characteristics considering objective functions which are contradictory to each other. These functions include fluid film thickness, film temperature, and power loss along with design variables vector, which consists of pad axial length to journal diameter ratio, pad arc length, bearing radial clearance, pad offset factor, and pad preload factor.

Design/methodology/approach

In order to improve performance characteristics of the pivoted‐pad journal bearing, the genetic algorithm (GA) was employed and the modeling of the bearing was represented with the finite element method. Also, a numerical method, global criterion, was conducted to validate the efficiency and applicability of the proposed method.

Findings

This paper utilizes the GA to solve multi‐objective optimization of the pivoted‐pad journal bearing performance governed by design variables such as pad axial length to journal diameter ratio, pad arc length, bearing radial clearance, pad offset factor, and pad preload factor for a range of rotational speed. The global criterion method (GCM) proves that the proposed method is very efficient and useful for the optimal design of the pivoted‐pad journal bearings. An acceptable results agreement between the GA and the GCM has been obtained. The GA is well suited to find the optimum solutions with a high probability since it starts with an initial set of solutions rather than a single solution. The GA explores different areas of search space in parallel and, it is good at exploitation.

Originality/value

With the help of the proposed method, it will be possible to have an idea about bearing geometric parameters on a more rational basis, and to better predict the dynamic performance of rotor systems supported on the pivoted‐pad journal bearings.

Details

Industrial Lubrication and Tribology, vol. 63 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 4 May 2010

Hamit Saruhan

The purpose of this paper is to implement an optimization approach for the tilting‐pad journal bearing using the genetic algorithm (GA), and compare the results with the method of…

Abstract

Purpose

The purpose of this paper is to implement an optimization approach for the tilting‐pad journal bearing using the genetic algorithm (GA), and compare the results with the method of feasible design (MFD).

Design/methodology/approach

The optimum design of a five‐pad tilting‐pad bearing is studied for the optimal performance, considering system minimum power loss along with design criteria such as: fluid film thickness, film temperature, and film pressure with respect to design variables consisting of pad axial length to journal diameter ratio, pad arc length, bearing radial clearance, pad offset factor, and pad preload factor.

Findings

The algorithms are repeated until no search direction can be found that will improve objective function without violating the constraints. Thus, the algorithms are performed for complete search to get the best possible solution of the design. The comparison mainly focuses on the empirical solutions. The GA obtained reasonably good results for the objective function and comparable to the MFD.

Originality/value

The availability of the GA is certainly of value because it allows the exploration of many different configurations of design variables and therefore also contributes to the better knowledge of the rotor‐bearing system behavior in general.

Details

Industrial Lubrication and Tribology, vol. 62 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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